Milan (AFP) - Keita Balde struck twice as Lazio ruined Francesco Totti's final derby as a player on Sunday with a thrilling 3-1 win over Roma that could also jeopardise their push for a top-two finish in Serie A.
Roma hosted their city rivals looking to maintain their fading title challenge to leaders Juventus after a 2-2 draw at Atalanta on Friday took their lead to nine points with four games remaining.
But Juve's slip-up wasn't enough to entice Roma on what should have been Totti's derby farewell as his final season in Italy's top flight draws to a close.
Luciano Spalletti's men physically turned up at the Stadio Olimpico, but mentally looked elsewhere as they struggled to impose their usual, fast-flowing game against a Lazio side battling for a Europa League place.
Roma enjoyed a bright start, Edin Dzeko notably firing over in the penalty box while under pressure.
But the red and yellow half of the Stadio Olimpico was stunned into silence when in the 12th minute, Balde collected a perfect through ball from deep in midfield to fire through the legs of Emerson Palmieri and wrong-footing Wojciech Szczesny in the Roma net.
Lazio could have done further damage, but Jordan Lukaku was denied what looked like a clear penalty when he was brought down by Fazio after he powered his his way into the area from the left wing.
Over-run in midfield and struggling for solutions in the final third, Spalletti turned to the Roma fans, gesturing for their vocal support as his side failed to fire.
Dzeko had a previous claim for a penalty waved away, but Roma's luck changed in dramatic fashion when Kevin Strootman came down following a swipe at his feet by Lazio defender Wallace.
Although television pictures suggested no contact had been made on the Dutch international midfielder, the decision stood and Daniele De Rossi stepped up to place his penalty inside Thomas Strakosha's near post to level on the stroke of half-time.
Dzeko flashed a drive off the post from Mohamed Salah's smart delivery after the break, but the Giallorossi were forever playing catch-up behind an energised and far more organised Lazio side.
Five minutes after the restart, Roma's defence stood back to allow Dusan Basta a free shot on goal and paid the price.
His effort deflected off a Roma defender before creeping past Szczesny inside his near post.
Totti, who has enjoyed only a handful of cameo appearances this season, replaced De Rossi for the final 17 minutes.
On another counter in the 85th minute, Senad Lulic was allowed to run half the length of the pitch, before finding Balde with a precision pass inside the area for the striker to slot past Szczesny and seal a famous derby victory over their bitter arch-rivals.