Inter came close to losing their first home league match in three years as they were held 1-1 at home to Sampdoria while Lazio went four points clear at the top of Serie A with a 2-1 home win against Cagliari. The result means AC Milan could leapfrog Inter into second place - two points behind the leaders - if they win away to Napoli on Monday night.
Stefano Guberti gave Sampdoria the lead but Samuel Eto'o's 15th goal in 13 games in all competitions earned a share of the spoils. Brazilian centre-half Lucio had the first clear sight of the goal on 10 minutes but Gianluca Curci made a point blank save from his close range volley.
Sampdoria were next to threaten as Antonio Cassano chipped to the back post where Guberti headed the ball back into the danger area and Giampaolo Pazzini stretched out a leg ahead of Walter Samuel but could only prod into goalkeeper Julio Cesar's arms. The livewire Brazilian teenager Coutinho then went on a jinking run down the left but Curci came out to smother at his feet with Eto'o firing the rebound into the side netting.
Inter were back on the attack after the break as more trickery from Coutinho created a chance for his compatriot Maicon but Luciano Zauri was ideally placed to clear his drive off the line.
Sampdoria went ahead on 62 minutes as Cassano shrugged off Cristian Chivu and crossed for Guberti to send an acrobatic volley goalwards, and although Cesar got his hands on it, the ball spun up and over the line. Inter came storming straight back and Curci saved with his legs from Coutinho while Wesley Sneijder fired wildly over the bar.
The visitors suffered a blow when goalkeeper Curci had to go off with a calf injury and his replacement Junior Da Costa's first task was to pick the ball out of his net 10 minutes from time. Coutinho, who had caused havoc all night, crossed from the left and Eto'o stole in at the near post to poke home.
"We didn't lack anything, we played well and created many chances," said Inter defender Waltuer Samuel. "There's a long way to go, Lazio are doing well but we're confident," warned the Argentine centre-back.
At the Stadio Olimpico, Lazio's dream start to the season continued as they downed their Sardinian visitors, now sitting worryingly second from bottom after a single victory in their eight games. Despite their lofty standing, Lazio coach Edy Reja refused to get carried away.
"It's not for us to talk about the title but we are showing that we're a top team," he said. "I want to congratulate my players, even though they made things complicated all on their own."
"After Cagliari's goal, which came from our lack of attention, there was too much apprehension and fear. That shouldn't happen to a top team," said the Lazio coach.
Sergio Floccari got Lazio off to a positive start, lashing home on 21 minutes after the ball fell to him when two Hernanes efforts were blocked. Stefano Mauri doubled the lead on 53 minutes in fortunate fashion as he stumbled and fell over, only for a cross from the left to hit him in the stomach and go in. Alessandro Matri's diving header from Andrea Cossu's cross six minutes later left Lazio hanging on at the end.
Lazio's city rivals Roma's turbulent start to the season continued as they were held to a 0-0 draw at rock-bottom Parma. Meanwhile Juventus failed to move into the top three as they were held to a 0-0 draw at Bologna. The visitors had a chance to go in front on 34 minutes when they were awarded a penalty but Italy goalkeeper Emiliano Viviano saved Vincenzo Iaquinta's effort to keep the score level.