Dario Cvitanich scored the only goal as Nice won 1-0 at home to Marseille who saw their Ligue 1 challenge dented in the process.
Cvitanich netted the only goal of the game five minutes before half-time when he rounded the keeper and scored into an empty net.
The visitors threatened after 15 minutes when Jeremy Morel set up Florian Thauvin on the edge of the penalty area but his first-time shot was beaten away by Nice goalkeeper David Ospina.
Nice could have taken the lead seven minutes later but Mahamane Traore shot inches wide after being presented with the chance by Jeremy Pied.
Cvitanich set up an opening for Pied after half an hour but his volley from the left side of the area was saved by Steve Mandanda.
Argentinian striker Cvitanich got the only goal of the game as half-time approached when he took a pass from Traore and went past Mandanda before applying a cool finish.
The post came to Nice's rescue a minute into the second half as Mathieu Valbuena passed to Gianelli Imbula whose shot from 20 yards came back off the upright.
Ten minutes later Ospina pulled off a fantastic save when he kept out a shot from Thauvin who had exchanged passes with Valbuena before hitting his effort on target.
Valbuena then set up Andre Ayew with a fine pass but after going past Gregoire Puel, Ayew's well struck shot came back off the post.
Marseille continued to press but could not find the goal which would have earned them a draw.
With 11 minutes remaining Ayew crossed to Andre-Pierre Gignac who met the ball with a firm close-range header but he was denied by Ospina who somehow stopped it from crossing the line.
The defeat leaves Marseille fourth in the Ligue 1 table, four points behind joint leaders Monaco and Paris St Germain and behind Lille on goal difference.
The win moved Nice up to fifth to lie behind Marseille on goal difference.