(CNN) -- Inter Milan opened a 10-point gap on city rivals AC Milan with a 2-0 win over Lazio in the San Siro on Saturday night.
Jose Mourinho's men went into the game without a win in their last three matches to give Milan a glimmer of hope, but made no mistake against a Lazio team who have Europa League aspirations.
Inter's star striker Zlatan Ibrahimovic proved the difference between the two sides and after some near misses it was his 58th minute strike which put them on the road to victory.
There appeared little danger as he gathered the ball on the edge of the area before firing home with a short backlift.
Ibrahimovic then set up Sulley Muntari for the decisive second on 70 minutes.
Milan are at Catania on Sunday as they bid to cut the gap to seven points again.
In the French league, Lyon's hopes of winning an eighth successive title took a nosedive as they lost 2-0 at Valenciennes.
Lyon went into the match six points adrift of leaders Marseille and four behind Bordeaux so victory was an imperative.
But the home side's Johan Audel scored a first-half double to give them the three points.
Marseille were later held 2-2 at home by Toulouse with Bordeaux able to draw level with them at the top if they beat Sochaux at home on Sunday.
In Scotland, Celtic moved four points clear of city rivals Rangers with a 3-1 win at Aberdeen.
Australian international Scott McDonald scored twice as Celtic had to come from behind at Pittodrie.
Chris Maguire gave Aberdeen a 22nd-minute lead before Celtic defender Gary Caldwell equalized near halftime.
McDonald gave the defending champions a crucial lead in the 72nd minute and scored the third in the 90th.
Rangers can cut the gap to a point with a win over Hearts on Sunday ahead of the Old Firm derby next weekend which may well decide the outcome of the title race.