(CNN) -- Zlatan Ibrahimovic scored the only goal from the penalty spot as AC Milan went back to the top of Serie A with a 1-0 home win over city rivals and reigning champions Inter on Sunday night.
Earlier, Lazio had briefly gone top as they beat Napoli 2-0 in Rome, but the defeat for European champions Inter drops them to fourth in the standings, six points behind their city rivals.
Milan won a fifth minute penalty when Clarence Seedorf released Swedish star Ibrahimovic and as he dragged back the ball had his legs taken from under him by Marco Materazzi.
Ibrahimovic got up to score from the spot and Milan might have gone further ahead as he volleyed just over while Robinho had the ball in the net on 22 minutes but was denied by a linesman's flag.
Inter had their best attacking moments through Wesley Sneijder and they looked set to come back into the match when Milan's Ignazio Abate saw red on the hour mark for a second yellow.
But they failed to take advance and Seedorf nearly added a second with a fierce shot from 18 meters.
In the German Bundesliga, reigning champions Bayern Munich moved up to sixth in the standings with a 3-0 win over Nuremberg.
Mario Gomez scored twice for the Bavarian giants, but they are still 12 points behind league leaders Borussia Dortmund, who kept up their relentless pace with a 2-0 win over Hamburg on Friday.
But coach Louis van Gaal has not given up hope his team can retain the title despite the big gap.
"We have to try and get at least 30 points, then we will have a chance," the Dutchman told AFP.
"I think Dortmund are very lucky at the moment, but they have a good team, they are well organized, play well and have a good coach.
"Their players really want to win."
Germany captain Philipp Lahm scored the other goal for Bayern from the spot in the 75th minute before Gomez rounded off the scoring.
He then missed a penalty three minutes from time at the Allianz Arena which would have completed his hat-trick.