(CNN) -- AC Milan's Serie A title challenge suffered a setback on Sunday as they were held to a 1-1 draw by struggling Lazio.
Following Inter Milan's 2-1 defeat at Roma on Saturday, Leonardo's side would have drawn level with the capital club, just a point behind Inter, with a victory on Sunday.
And the home side looked like they would claim the three points when Marco Borriello put them ahead from the penalty spot.
But Lazio did city rivals Roma a favor by levelling through Swiss international defender Stephan Lichsteiner in the 32nd minute.
The result means Inter lie on 63 points with seven matches remaining, a point ahead of Roma and three clear of Milan in one of the tightest Italian title races in recent seasons.
In other matches, sixth-placed Juventus returned to form after successive defeats to Sampdoria and Napoli -- beating Atalanta 2-1 thanks to an 82nd minute Felipe Melo header.
However, Sampdoria slipped from fifth to seventh place after a 1-1 home draw against Cagliari, for whom Nene scored the equalizer before being sent off in stoppage time.
The day's big winners were Fiorentina, who thrashed struggling Udinese 4-1 with Alberto Gilardino amongst the goals again.