Inter Milan recovered from their midweek Champions League mauling by Arsenal to hand Italian champions Juventus their first defeat of the season with a shock 3-1 win at the Delle Alpi stadium on Saturday.
Argentine striker Julio Ricardo Cruz struck twice as Inter put their 5-1 home defeat by Arsenal behind them with a superb display to end Juve's 11-month unbeaten home record in Serie A.
The result was Inter's first league victory at Juventus in over 10 years -- their last was 2-0 in March 1993 -- since when they have managed just two draws and one goal in the fixture.
Juventus will lose top spot in the standings if AS Roma or AC Milan win on Sunday.
Cruz fired Inter ahead in the 12th minute with a brilliantly taken free kick.
The Argentine, deputising for the injured Christian Vieri, added the second in the 69th minute, reacting well to fire home after his first shot was blocked by Juve keeper Gianluigi Buffon.
With Juventus pushing forward in search of a way back into the game, 19-year-old Nigerian Obafemi Martins raced on to a Cruz flick and danced past Nicola Legrottaglie before slipping the ball under Buffon to make it 3-0.
Juve defender Paolo Montero pulled one back for the champions in the final minute but that was no consolation at the end of a game which pushed Inter right back into the title race under new coach Alberto Zaccheroni.
Lazio also suffered a surprise defeat 3-0 away to Siena thanks to two first-half goals from Brazilian Rodrigo Taddei and a late strike from his compatriot Fernando Menegazzo.
After Dejan Stankovic missed a glorious chance for Lazio in the 19th minute, firing high and wide from just two metres out, Taddei put Siena in the lead, blasting home after the Lazio defence had failed to clear a cross from Gianni Guigou.
Two minutes later the Brazilian doubled the advantage after poor work from Lazio's Serbian defender Sinisa Mihajlovic.
Nicola Ventola whipped the ball away from Mihajlovic as the defender was trying to usher the ball out for a goal kick and fired over a low cross which Taddei slotted home.
Siena's Norwegian striker Tore Andre Flo then missed an easy chance, firing over when unmarked inside the area, before Stankovic was sent off in the 67th minute for dissent.
Menegazzo wrapped up the victory in injury time after being set up by the outstanding Taddei.
The result moved Siena up to seventh place, while Lazio stayed fifth.
