Zlatan Ibrahimovic's penalty helped AC Milan beat 10-man Genoa 2-0 on Friday to provisionally move top of Serie A following a game that was suspended for around 10 minutes after tear gas filled parts of the Stadio Luigi Ferraris.
Ibrahimovic struck in the 56th minute after he was brought down in the area by former Milan defender Kakha Kaladze, who was also dismissed following a second booking.
It was Ibrahimovic's fourth goal in three games and his eighth in Serie A this season.
"We're playing very well, with a lot of confidence, even away from home, where we're dominating possession and attacking," the Sweden striker said. "So what the other teams do, they do, but we have to continue with this spirit and this confidence. If we keep going as we are then I don't see what can upset us."
Antonio Nocerino, who played five games for Genoa, doubled Milan's lead in the 79th, shortly after Robinho had missed a good opportunity for the visiting side.
Milan moves a point clear of Juventus, which faces second-from-bottom Cesena on Sunday.
The players left the field temporarily in the first half because of the tear gas, which was reportedly released by police officers outside the stadium.
Alexandre Pato, who scored for Milan in the 4-0 victory over Chievo last Sunday, missed the game with a fever, so Robinho started up front with Ibrahimovic.
Milan could have gone in front after just 90 seconds. Ibrahimovic sent a long ball over the defense to Nocerino, who raced into the middle of the area, but Marco Rossi did well to muscle him off the ball and Genoa goalkeeper Sebastien Frey gathered up the danger.
Minutes later it was Genoa who had a decent opportunity as Rossi set up Lucas Pratto, but Thiago Silva cleared just as the Argentine striker was about to shoot.
Milan could easily have been 2-0 up as Robinho first blazed his shot over the bar before Nocerino failed to score what seemed a certain goal against his old team. The midfielder latched on to Ibrahimovic's long pass but shot straight at the onrushing Frey.
The game was then suspended in the 15th minute when the tear gas was released.
Most of the players returned to the dressing room, while some fans were visibly affected. Local media reports said the tear gas was released by police to disperse some supporters outside the stadium.
Milan missed a good chance to take the lead 10 minutes after the game restarted as Kevin Prince Boateng released Robinho down the left flank. The Brazilian put in a low ball across the face of goal, but there was no Milan player there to take advantage.
Genoa had its best opportunity in the 34th when it won a free kick on the far right of goal. Miguel Veloso tried to surprise Marco Amelia with a swerving shot which the Milan goalkeeper did well to tip over the bar.
Genoa tried its luck again from a tight angle minutes later as Giandomenico Mesto's shot flew just the wrong side of the far post.
Veloso could have given Genoa a first-half lead with a powerful 20-yard effort which Amelia did well to smother.
But the hosts made their task a lot tougher shortly after the interval. As Ibrahimovic controlled the ball and attempted to lift it past Kaladze, the Genoa defender caught the Sweden striker's leg and brought him down.
Kaladze, who won eight trophies in nine seasons with Milan, was handed a second yellow card and dismissed. Ibrahimovic stepped up to the spot and lashed a perfect shot into the top left, sending Frey the wrong way.
Robinho should have doubled Milan's lead four minutes later as he missed a great opportunity. Nocerino stole the ball from Dario Dainelli as it was about to go out for a goal kick and crossed for Robinho, who was practically on the goal line but somehow managed to blaze over from point-blank range.
"He's a good person with a big heart," Ibrahimovic said. "These things have also happened to me. At the moment my shots are going in and his aren't. But as soon as one goes in, others will too."
Nocerino scored from almost exactly the same position 11 minutes from time when he fired home Boateng's cross.
Genoa had missed a chance to level five minutes earlier. Alexander Merkel found Rossi in the area, and the Genoa captain sent a neat sidefooted shot towards goal which sailed just past the right hand post from six yards.