Kevin-Prince Boateng kept AC Milan in the Serie A title hunt and sent the club who brought him to Italy closer to relegation with the only goal against Genoa on Wednesday night.
The Ghana international kept Milan's Scudetto challenge on track with an 86th-minute goal in a frustrating match for Massimiliano Allegri's hosts.
Genoa, who remain just one point above the relegation zone, lost Bosko Jankovic to a red card midway through the second half.
Genoa had their third coach of the season on the bench, with Luigi De Canio replacing Alberto Malesani after his second spell in charge came to an end after Sunday's 4-1 defeat at home to Siena.
In front of their new boss, Genoa were in stubborn mood on Wednesday night and Sebastien Frey, who has conceded more goals than any other goalkeeper in Serie A this season, showed why he is nevertheless regarded as one of the best in the division.
He denied Zlatan Ibrahimovic from close range before thanking Davide Biondini for blocking a shot from Boateng on the hour.
It looked like Milan were not going to find a way through, not even after Jankovic was sent off for a second booking.
But with news filtering through that leaders Juventus had taken the lead at Cesena, Boateng struck against the side who signed him two years ago before immediately sending him out on loan to the Rossoneri.
Boateng, who has since made the move to Milan a permanent one, threaded the ball past Frey from a tight angle to ensure Milan remain three points behind Juve with four games remaining.