Milan fell 1-0 to a 54th-minute Cedric Konan goal at Lecce while leaders Juventus were held to a 0-0 draw at bottom club Treviso.
Despite the disappointing result and performance from Juventus, Fabio Capello’s side extended their lead over Milan to nine points with just six games remaining.
Inter Milan made easy work of lowly Messina, winning 3-0 with all the goals coming inside the opening 26 minutes.
The victory moved Inter to within two points of their city rivals.
AC Milan, who rested several of their top players including Ukrainian striker Andriy Shevchenko and Brazilian Kaka, dominated the opening 45 minutes at Lecce but home keeper Vincenzo Sicignano was in inspired form.
Argentine Santiago Solari put Inter on their way, lobbing Messina keeper Marco Storari from edge of box with an instinctive strike in the 15th minute before Nigerian Obafemi Martins headed in a Kily Gonzalez cross to make it 2-0.
Solari wrapped the game up in the 26th minute, slotting home from close range after Storari had pushed out a Marco Materazzi header from a corner.
Yesterday, Fiorentina missed the chance to strengthen their position in the UEFA Champions League places after a 1-1 home draw with Roma.
Chievo remain sixth after a 2-1 victory over Livorno, while Empoli boosted their chances of Serie A survival after an entertaining 3-3 draw with Lazio at Rome’s Stadio Olimpico.
In Spain, Valencia climbed back to third in the table after getting the better of Cadiz in an eight-goal thriller, while Osasuna were thumped 4-0 at home by Getafe yesterday.
Valencia took advantage of Osasuna’s lapse, but they made their fans sweat.
David Villa fired Valencia ahead inside two minutes. Cadiz were level on 11 minutes through Fernando Enrique, but goals before the break from Miguel Angel Angulo and David Navarro had Los Che in the driving seat.
Angulo netted his second on 55 minutes, but Cadiz replied 60 seconds later through Jonathan Sesma.
Villa netted Valencia’s fifth on 66 minutes, but Sesma ensured the home side had to battle for the final 15 minutes when firing home to make the score 5-3.
On Saturday, a classy goal by Brazilian striker Ronaldo and some outstanding goalkeeping from Iker Casillas helped 10-man Real Madrid come from behind to hold leaders Barcelona to a 1-1 draw at the Nou Camp.
Real fell behind to a controversial Ronaldinho penalty midway through the first half and suffered another setback soon after when Roberto Carlos, who had conceded the spot kick, was red carded minutes later for saying something to the referee.
But Real salvaged a draw and some pride when Ronaldo roared on to a clever through-ball from Julio Baptista and netted with a deft chip eight minutes before the break.
Also on Saturday, Villarreal warmed up for tomorrow’s Champions League quarter-final, second leg against Inter Milan when they secured their first Primera Liga win in five outings with a 1-0 victory at Real Zaragoza, while Real Sociedad beat Malaga 3-0.
In Germany, Bayern Munich had to come from behind twice to earn a 2-2 draw at home to bottom club Cologne on Saturday, a result that gives a glimmer of hope to the chasing pack in the Bundesliga.