Champions League: Five talking points ahead of the last 16 ties

1) Will Chelsea get over-run in central midfield?

PSG’s monopoly over Ligue 1 has reached frightening new heights this season, increasing the pressure on Laurent Blanc to win the Champions League and complete the sculpting of France’s first super-club. Chelsea’s performances have gradually improved under Guus Hiddink and, although their league form remains erratic, expect the gritty, sweat-soaked Chelsea of old to re-emerge on Tuesday night.

Blanc’s side averaged 60% possession and 90% pass completion in the group stages, which included two possession-dominant performances (59% in each) against Real Madrid. Blanc’s high tempo, short-passing aesthetics are suffocating and Chelsea can expect to receive similar treatment; they will happily conceded territory on unfamiliar soil. The problem is that Thiago Motta, Adrien Rabiot, and Blaise Matuidi revolve with wonderful fluidity in the middle (averaging a combined 207.5 passes per match) and this could out-wit and out-manoeuvre Chelsea’s often lacklustre central midfield.

Nemanja Matic has recovered from his 2015 wobble but his two partners – John Obi Mikel and Cesc Fabregas – remain fragile. Mikel often disappears against quick tiki-taka midfields (he was overawed in the recent 3-3 draw with Everton, when Muhamed Besic and Gareth Barry amassed 123 passes between them), and Fabregas rarely tracks back with the discipline needed against more agile – and more tactically intelligent – opponents.

As PSG counter-counter (Chelsea will sit deep and pour forward when the chance arises) Fabregas, Pedro, and Eden Hazard will most likely jog listlessly back to defend, leaving enormous gaps for Matuidi and Rabiot to exploit. Given that Angel Di Maria loves to drift inside and collect the ball centrally, it is easy to imagine Matic shuttling frantically amidst a swarm of Parisian bodies.

2) Will Arsenal be brave and press Barcelona from the front?

It takes great courage to follow the tactical template created by Malaga, Deportivo and Atletico this season, but the only way to stop Barcelona is to ignore your instincts and embrace a system that must feel like suicide; press high and attack from the front, and the deadly trio of Neymar, Leo Messi, and Luis Suarez can – with a bit of luck – be stopped.

A decade of cowering in a defensive shell has rarely found success against Barcelona’s dominant style, and it is becoming clear that a fearless approach based on high pressing can disrupt Barca’s flow and cut them off at the source. On average, Malaga, Deportivo, and Atletico attempted 9.3 tackles and 5.2 interceptions in the opposition half, scoring a total of five goals and conceding six. It is by no means a fool proof system, but – as Valencia proved when their ultra-defensive shell was shattered a fortnight ago – it represents the best chance of success.

Arsenal are well suited to attempting something similar; they play with a very high line at the Emirates and press frantically when possession is lost in the opposition half. However, after years of stubbornly refusing to adapt this model against more accomplished sides, Arsene Wenger has recently begun to retreat territorially. This season alone they have beaten Bayern Munich, Man United, and Man City whilst holding the minority of possession; any attempt to treat Barcelona with the sort of humility shown against Bayern will be treated ruthlessly.

3) Can Spalletti’s back three stump Ronaldo, Benzema, and James?

Roma fans are delighted to see Luciano Spalletti return to the dugout just as Roma’s season had threatened to stagnate, and a run of four successive victories has restored optimism inside the Stadio Olimpico. What’s more, his unexpected switch to a narrow 3-4-2-1 gives Wednesday’s match fresh intrigue; Zinedine Zidane has enjoyed a comfortable beginning in Madrid but it remains to be seen if he is tactically articulate.

Cristiano Ronaldo has excelled under Zidane - contributing seven goals and three assists from his favoured inside left position – but this is the first time he will be faced with a flat back three that will allow the “spare” centre-back to double up with Maicon. This is likely to be the key battle, and although during sustained pressure this could stump Ronaldo, Roma’s propensity to pass out from the back (the three defenders made a combined 168 passes away at Juventus) should make for a fascinating match-up.

Madrid will not often be faced with a deep-lying wall of bodies, but instead will have to battle for possession in central midfield; as a result, Real’s front three will occasionally be released into counter-attacking space, creating interesting three-on-threes. Predicting the tactical pattern or goal count in this one is difficult, but whatever happens we can anticipate a fascinating, swirling tactical stand-off.

4) Will Douglas Costa unlock Juventus?

Juventus are not afraid to absorb pressure in compact rows of four. They average 47% possession in the Champions League this season and completed the double over Manchester City by conceding the majority of the ball; expect a ruthlessly tight defensive structure against Bayern coupled with quick transitions on the counter. As the injuries mount up, Douglas Costa represents Bayern’s best chance of picking Juve apart.

Costa has had a phenomenal first season in Germany. His unusual combination of power and delicacy when dribbling through the centre of the pitch has played a crucial role in piercing the stubborn tactical models of Bayern’s opponents, and with so many key players on the injury table his form has never been more important.

Expect Stephan Lichtsteiner to remain narrow in order to track Costa’s movement as he attempts to cut inside, with Sami Khedira sitting in that centre-right zone – ready to shimmy across and help out his right-back. Right winger Juan Cuardrado plays a crucial role in remaining high up the field and instigating the counter, thus Khedira must ensure Juventus are not light on this side. Costa only needs one chance, and anything other than a win on home soil will surely see the Italian champions knocked out.

5) Can Yarmolenko exploit Man City’s injury crisis?

In drawing Dynamo Kyiv Manchester City won the lottery, but their haphazard form has cast doubt over their ability to overcome the conditions in Ukraine. In the 2-1 defeat to Tottenham Manuel Pellegrini – with little other option thanks to key injuries - played Raheem Sterling on the left; his unwillingness to track back effectively could leave Gael Clichy with too much to do against Andriy Yarmolenko.

Yarmolenko has already scored twice in this season’s Champions League and averages 2.6 key passes per game (most in Dynamo squad). He is the chief orchestrator of the Ukrainian’s counter-attacks, using his speed and agility to gain them ground (41% of their attacks come down the right, the 4^th most in the Champions League).

Although Man City should be able to dominate this match, it will worry City fans that Yaya Toure, Sterling, and David Silva will all hover so high up the pitch, given that this situation so frequently leads to opponents scoring on the counter. Yarmolenko, galloping down the wing in acres of space, is a troubling thought.