Serie A - Bologna win as Lazio self-destruct
Lazio lost ground on the top two places in Serie A after they suffered a disastrous 3-1 home defeat to Bologna at the Stadio Olimpico.
From the subsequent free-kick, Rene Krhin struck to make it 3-1 and secure Bologna's first win against the Romans in their last 12 visits to the capital.
Things got worse for Lazio just before half-time when midfielder Matuzalem was shown a straight red card for putting his hand into Diamanti's face.
The defeat means Lazio are now five points behind second-placed Juventus and nine behind leaders AC Milan. However, they retain third place, the final Champions League spot, after Udinese lost 1-0 at lowly Novara. Lazio are now two points above Udinese and Napoli, who are fourth on goal difference.
Bologna climb up to ninth in the table as they extended their unbeaten run in the league to five matches.
Bologna took the lead on 11 minutes when Lazio failed to deal with a corner, earned when Diamanti surged forward on the break and drew a fine save from goalkeeper Federico Marchetti.
From the resulting set piece Marchetti saved Andrea Raggi's initial effort but Bologna captain Portanova's follow-up effort from inside the six-yard box was struck hard enough to squirm past the two defenders on the line.
Diamanti almost scored a memorable second for Bologna when his whipped corner flew over Marchetti and bounced off the top of his crossbar, but he soon claimed his fourth goal of the season on 28 minutes in any case.
Marchetti came out of his area to head the ball clear before Robert Acquafresca – preferred up front to veteran striker Marco Di Vaio – could reach it, but only succeeded in directing it at Diamanti. The former West Ham man struck the ball back past the keeper from 35 yards out to double the visitors' lead.
Lazio's evening descended still further when Matuzalem was sent off just before the break for his hand-off on Diamanti. There appeared to be little aggression in his action, but the referee did not hesitate in sending the Brazilian off.
There was a glimmer of hope for Lazio 10 minutes after the break when Rubin's misjudged backpass rolled past his own keeper and agonisingly into the net. But no sooner had they taken one step forward than they took two back.
As the hour mark approached Gaston Ramirez hurtled through the centre, clean through on goal, only to be tripped by Gonzalez right on the edge of the area. The Uruguayan was dismissed, and while Diamanti struck his free-kick against the wall Slovenian midfielder Krhin drilled a clinical low strike home from 20 yards for his first ever Serie A goal.
With an advantage of two goals and two men, there was a degree of complacency which crept into some of Bologna's players, but Lazio were not able to take advantage as their opponents took their foot off the gas.
Lazio boss Edy Reja brought on Antonio Candreva and Libor Kozak in the final 20 minutes, but his team never looked like avoiding a defeat which sees Bologna draw level in the all-time head-to-head between the two clubs with 44 wins apiece.
In Sunday night's other match, Udinese were another team whose bid for a return to the Champions League suffered a blow after they lost 1-0 at relegation strugglers Novara.
Brazilian striker Jeda scored only his second league goal of the season, and his first since October, 16 minutes into the clash between the two northern sides.
Despite the win, Novara remain in 19th place, 11 points from safety. Udinese end the weekend in fifth place, below Napoli on goal difference after the Partenopei beat Cagliari 6-3 on Friday night despite Edinson Cavani and Christian Magio starting that match on the bench..