Antoine Griezmann penalty helps Atletico take 1-0 lead to Leicester City.
Cristiano Ronaldo reaches 100 European club goals with double to beat Bayern Munich.
Arturo Vidal put Bayern ahead only to miss first half penalty. Javi Martinez sent off for two bookable offences.
Recap: Borussia Dortmund 2-3 Monaco. Match re-staged after suspected terror attack.
Dortmund defender Marc Bartra recovering after surgery to treat injured hand.
Champions League results [7:45pm BST kick-off]
Atletico Madrid 1-0 Leicester City
Bayern Munich 1-2 Real Madrid
Well we have reached half-time in each of our quarter-final ties in the Champions League, with Atletico Madrid, Monaco, Real Madrid and Juventus the front-runners to qualify. Work to do for Leicester, Borussia Dortmund, Bayern Munich and Barcelona in next week's second legs.
We're back with full coverage of the Europa League tomorrow, when Manchester United take on Anderlecht. But until then, it's a very goodnight.
Full time: Bayern Munich 1-2 Real Madrid
Another night in Europe dominated by Cristiano Ronaldo. He reached 100 European club goals with a second half double to beat Bayern Munich. The hosts had a grip on the tie through Arturo Vidal's header, but the Chilean's missed penalty in the first half sparked their decline. Javi Martinez's red card ensured the Germans could not respond in the second period and they have an uphill task come the second leg.
Another Real Madrid goal chalked off in added-on time as Sergio Ramos heads home but he came back from an offside position before nodding in. Three added minutes at the Allianz.
Full time: Atletico Madrid 1-0 Leicester City
Atletico dominate the 90 minutes but will take just a one-goal lead to the King Power Stadium after Leicester show the fighting spirit which has defined their fairytale over the last 18 months. Antoine Griezmann scored the only goal from a debatable penalty and though the Foxes offered very little in attack, Atletico also seemed content with the narrow win. All to play for next week.
Cristiano Ronaldo celebrates as Real Madrid turn it around at Bayern Munich.
Ángel Correa weaves in and out of the Leicester defence and feeds the ball arcoss the six-yard box, but there isn't a single Atletico player on hand to put the ball. The Foxes penned in on their own area. Can they survive?
Ball in the net for Real but Benzema is just offside as he collected Marcelo's vollyed cross.
Six minutes left and Leicester are living dangerous as Atletico search for what could be a pivotal second goal. Benalouane is in the right place at the right time to hack the ball behind as Griezmann prowled.
GOAL! Bayern Munich 1-2 Real Madrid (Cristiano Ronaldo)
Bayern's resolve, and more importantly Manuel Neuer, is finally beaten. Ronaldo registers his 100th European club goal as he pokes home Danilo's left-sided cross. The 10-men are breached and the 11-time winners are on course for the last four.
Jamie Vardy, who is a yellow card away from missing the second leg, comes off and record signing Islam Slimani comes on for the final 13 minutes. Needs to hold the ball up.
Karim Benzema should really have Real ahead but a save with his legs from Neuer keeps the scores level. How important might that be come full-back in the Bernabeu?
Thomas Partey replaces the poor Fernando Torres. Sticks out like a sore thumb does the Spaniard. Leicester will be a little disappointed to see the back of him.
Leicester holding their own in this second half, with Atletico not really offering anything in an attacking sense. Eighteen minutes to go, ans a 1-0 deficit would be a good result for the Foxes.
Red card: Javi Martinez (Bayern Munich)
This tie has been turned on its head in the second half. Bayern are down to 10 men after Martinez picks up two yellows for fouling Cristiano Ronaldo in successive minutes. Thirty minutes or so left for Real to take advantage and take a lead back to Madrid.
Action at both ends in Madrid. Riyad Mahrez wants a penalty when he goes over a challenge by Koke - but Jonas Eriksen waves away the appeals.
At the other end, Fernando Torres glides through the Leicester defence but slips at the vital moment and the ball skews wide without troubling Schmeichel.
Robert Huth out of the second leg after picking up a second booking for a foul on Griezmann. Silly foul after the Frenchman had turned away. Needless.
Leicester causing problems almost exclusively from long throws and they come close to equalising when Robert Huth's effort is blocked and the loose ball falls to Mahrez, who curls high and wide.
Six months after his last.
GOAL! Bayern Munich 1-1 Real Madrid (Cristiano Ronaldo)
Less than two minutes into the second half Real Madrid get their crucial away goal. Carvajal crosses and Ronaldo peels away and turns a volley into the corner. The Allianz Arena is silenced.
Yohan Benalouane booked as Leicester desperately attempt to snuff out another Atletico attack. Leicester playing second fiddle once again.
Andy King on for Shinji Okazaki for Leicester. Strange more, not least the player who has come off than on. Back underway in Madrid. Some way behind in Munich.
Half time in both Champions League quarter-finals, and the drama has well and truly continued.
In Madrid, hosts Atletico lead Leicester by an Antoine Griezmann penalty - awarded after he was fouled outside the area by Marc Albrighton.
In Munich meanwhile, Arturo Vidal has turned from hero to villain. The Chilean opened the scoring with a stunning header, before he smashed a harshly awarded penalty over the bar.
Half time: Bayern Munich 1-0 Real Madrid
Justice done in Munich. Carvajal shoulders the ball behind and inexplicably a penalty is awarded. Arturo Vidal steps up and blasts the ball, Chris Waddle esq, into the stand. Obviously an awful penalty, but the right result in the end.
Half time: Atletico Madrid 1-0 Leicester City
PENALTY TO BAYERN MUNICH
Jamie Vardy gives away a soft foul in the attacking this. The England man is a booking away from missing the second leg and has already got away with three infringements. Walking a disciplinary tightrope.
Cristiano Ronaldo has not scored in his last six Champions League appearances but he almost breaks than duck with a turn and shot which Neuer pushes away. Real have been the better side in this first half, but it is Bayern with the lead.
Antoine Griezmann sends Kasper Schmeichel the wrong way to put Atletico ahead.
The Algerian has been hopelessly poor tonight, again.
On second viewing, Albrighton clearly takes Griezmann out outside the penalty area. The Frenchman's momentum - he was travelling at some speed - took him into the box so perhaps the referee can't be blamed but it is a mistake nonetheless.
Aruto Vidal opens the scoring for Bayern Munich.
GOAL! Atletico Madrid 1-0 Leicester City (Antoine Griezmann)
Leicester get caught badly on the break and Marc Albrighton commits a cynical foul on the Frenchman to prevent him bursting deep into the penalty area. Schmeichel saved two spot-kicks in the last 16 but Griezmann sends him the wrong way to put the home side ahead.
PENALTY TO ATLETICO MADRID
GOAL! Bayern Munich 1-0 Real Madrid (Arturo Vidal)
A goal out of nothing for the home side. A corner whipped in from the left finds the head of Vidal, who powers a headed through the hands of Navas and into the roof of the net.
Brief spell from Bayern at the Allianz Arena and it eds with David Alaba trying one from range which balloons over. With Robert Lewandowski, it would be fair to say the hosts look a little directionless.
In Munich, another side from Madrid - Real - are in the ascendancy and they go within inches of taking the lead and grabbing a crucial away goal. Carvajal's deep cross picks out Benzema, who heads down and onto the crossbar, with the fortunate Manuel Neuer clutching the loose ball. Big chance.
It's all Atletico in the early moments here and Leicester can't stem the flow. Do Craig Shakespeare's side have a plan B?
So much verve and quality about the Atletico display in this opening 12 minutes and Griezmann hammers over from 30 yards. Leicester will field those all day if they have to, but you fancy Kasper Schmeichel will be kept busy tonight.
Robert Huth fails to head clear and Carrasco has the chance to take aim, but volleys wide. One-way traffic so far it must be said for the La Liga side.
Atletico into their stride however and after Schmeichel saves easily from Torres,he can't get anywhere near Koke's effort from range which smashes against the post. A warning sign for the visitors.
First glimmer for Leicester in Madrid, who will be very happy to sit back and let Atletico dictate; attempting to hit them on the break. Vardy scampers away in the left-hand channel of the penalty area, with his cross-come-shot flying across goal but there was no Foxes player available to score.
Full time in Dortmund and the demands of playing less than 24 hours after their team coach was bombed, leading to an injury to Marc Bartra, has proven took much for Borussia Dortmund as they were overwhelmed 3-2 by a Monaco side who continue to thrill in this competition.
Teams are out and that famous Champions League anthem is blaring out in both Madrid and Munich. Another night of drama in Europe's premier club competition awaits. Updates on the way.
No official line from Leicester regarding the behaviour of their fans in Madrid this afternoon. Tempted to say we might not get anything until after the game. Manager Craig Shakespeare will undoubtedly be questioned on such events. Once again football is overshadowed for the wrong reasons.
Atmosphere building ahead of a historic night in the history of Leicester City.
Craig Shakespeare on BT Sport: "Everyone's relaxed, eager to get started. I've told the players to be positive and be themselves. We know what we're about. I think it will be a bit more tactical tonight due to the nature of the tie. Of course, we must respect Atlético's qualities."
A big night for Leicester ruined by their supporters it must be said. These fans seemed to have enjoyed themselves however.
Atletico yet to confirm their team, but many are suggesting that the below is the line-up.
Five changes in all for Leicester. Back in come Danny Simpson, Christian Fuchs, Wilfred Ndidi, Riyad Mahrez, and Shinji Okazaki.
Leicester team in from the Vicente Calderon.
Half time in Dortmund where the home side unsurprisingly are not at the races, with Monaco leading 2-0 at the break. Kevin M'Bappe's opener has been added to by Sven Bender's own goal. A thoroughly miserable week for the Germans has got a whole lot worse.
So how might Atletico and Leicester line up in Madrid?
Tiago, Augusto Fernandez, Miguel Ángel Moya and Sime Vrsaljko will all miss the first leg for Atletico, while Kevin Gameiro and Nicolas Gaitan are doubtful with fitness concerns.
Leicester are without captain Wes Morgan while Nampalys Mendy is the only other absentee for the Premier League champions.
And Bayern Munich have followed. Robert Lewandowski missing as expected.
Somewhat early, the Real Madrid team has dropped.
On a night where football should prevail, I start on a sour note with news that Leicester City fans have been clashing with police ahead of the game in Madrid. Videos, including this one, are doing the rounds on social media.
After the events prior to the postponed quarter-final tie in Dortmund, it seems slightly perverse to be turning attention to football, but the schedule dictates that the show much go on. Atletico Madrid, Leicester City, Bayern Munich and Real Madrid will all be hoping to make the headlines about football tonight, after the sobering incident in Germany yesterday which left Marc Bartra with a series of injuries.
Our focus will be on the fortunes of Leicester City, who are the only Premier League representative in the last eight of the competition. The Foxes have lost just once since Craig Shakespeare took charge from Claudio Ranieri, and though they are once again heavy underdogs tonight in the Spanish capital their plucky status undid Sevilla in the last 16; and they will fancy causing another upset again a La Liga opponent.
All the teams news from Madrid and Munich on the way ahead of the 7:45pm BST kick-offs.
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