Inter Milan won 2-0 at Roma shortly after AC Milan beat Lazio by the same scoreline on Saturday.
The Rossoneri could be counting the cost of that match, however, as key forward Rafael Leao limped off injured just four days before the Champions League semi-final.
Milan closed the gap between them and second-placed Lazio to three points after an Ismael Bennacer strike and a stunning Theo Hernandez goal.
Milan was one point behind Inter and Juventus, who play at Atalanta on Sunday.
“I'm happy with the performance and for the win, it was too important a match for us,” Milan coach Stefano Pioli said.
“What was important was to play well and we did that even without Leao.”
“I don't think it's serious but we'll evaluate it tomorrow. He stopped in time, he was very calm and that gives me good hope.”
Atalanta and Roma were five points below fourth-placed Inter.
The two Milan clubs meet in the first leg of the Champions League semi-finals on Wednesday. The return leg is the following Tuesday.
Leao limped off in the 11th minute shortly after pulling up and clutching the top of his right thigh.
Milan nevertheless took the lead six minutes later. Lazio defender Nicolo Casale attempted to pass out from his area, but Bennacer stole the ball and played a one-two with Olivier Giroud before firing past Ivan Provedel.
Milan doubled their lead in stunning fashion in the 29th when Hernandez collected a pass inside his own area from goalkeeper Mike Maignan and raced almost the whole length of the field before unleashing a shot into the top right corner.
Inter Milan recorded its fifth consecutive win in all competitions. It has also conceded just one goal in that run.
Inter broke the deadlock in Rome in the 33rd minute. Denzel Dumfries ran onto a fantastic Marcelo Brozović throughball and whipped in a cross from the right that Federico Dimarco fired in from a tricky angle.
Roma midfielder Bryan Cristante got the last touch on the ball as he desperately tried to keep it from going in, but the goal was awarded to Dimarco.
There was a bit of fortune for Inter's second in the 74th. Roma defender Roger Ibanez intercepted a long ball over the top but accidentally gave it back to Lautaro Martínez who sent Romelu Lukaku through for a relatively straightforward finish into the bottom left corner.
Martínez also hit the crossbar late on.
AAP
