PARIS, April 19 (Reuters) - Olympique Lyon edged closer to a record seventh consecutive Ligue 1 title by fighting back from a goal down to win 2-1 at 10-man Racing Strasbourg on Saturday. Lyon have 71 points with four matches left, seven ahead of second-placed Girondins Bordeaux, who play their game in hand at Toulouse on Sunday. Colombia striker Wason Renteria put Strasbourg ahead on 20 minutes before the home side had Gabon forward Eric Mouloungui sent off for a second booking on the stroke of halftime. Lyon stepped up a gear in the second period with headed goals from midfielder Mathieu Bodmer and Italy defender Fabio Grosso. The win was marred by a knee injury sustained by Lyon and France striker Karim Benzema, who had to go off after 36 minutes. At the other end of the table, two goals from Aruna Dindane led struggling Racing Lens to a 3-2 home win over Sochaux. Lens stayed fourth from bottom but moved three points clear of the relegation zone. Paris St Germain, one place below Lens, are in danger of going down for the first time after losing 3-0 at Caen. The atmosphere was tense at Caen and a PSG supporter invaded the pitch and started running towards visiting goalkeeper Mickael Landreau before heading back. Police then moved in and stood on the pitch in front of the stands occupied by PSG fans. Surprise packages Nancy are third after a 1-1 home draw with Le Mans. Nancy are a point ahead of Olympique Marseille, who host Lille on Sunday.