(CNN) -- Inter Milan's defense of their Serie A title may have taken a fatal blow with a 1-0 defeat at arch-rivals Juventus Sunday night.
It left Leonardo's men eight points adrift of city rivals AC Milan, who romped to a 4-0 home win over Parma 24 hours earlier, but they still have a game in hand.
Alessandro Matri scored the winner for improving Juve in Turin after 30 minutes to improve their chances of claiming a Champions League spot.
Frederik Sorensen's cross was missed by Ivan Cordoba and Matri headed home from close in.
It was only the second defeat for Inter under their new Brazilian coach who replaced Rafael Benitez and they offered little as an attacking threat.
The best chance came eight minutes from the end as Samuel Eto'o played a one-two with Wesley Sneijder but Gianluigi Buffon came out sharply to block the Cameroon star's effort.
Earlier, Lazio maintained their title bid with a 2-0 win at Brescia to stay third, seven points adrift.
Goals from Alvaro Gonzalez after 18 minutes and Libor Kozak just before the hour mark secured three vital points for the capital side.
Coach Edy Reja asked the fans to be patient after his side have slipped in recent weeks.
"We were top and then second and then we lost a few places but there are times throughout a long season in which it's normal to have a bad spell," he told AFP.
Udinese also kept up their pursuit of a European place with a 3-0 win at struggling Cesena.
Antonio Di Natale scored a double allied to a strike by Gokhan Inler as they stay fifth.
But Palermo saw their hopes nosedive with a shock 4-2 defeat at home to Fiorentina.