PARIS, Aug 31 (Reuters) - A second-half goal from Karim Benzema earned Olympique Lyon a 1-0 win at arch-rivals St Etienne as the seven-times French champions joined Olympique Marseille at the top of the Ligue 1 standings on Sunday. The France striker netted 11 minutes into the second half with a fine curling shot to give Lyon all three points. Lyon, who have yet to concede a goal this season, have 10 points from four matches and trail leaders Olympique Marseille, 2-1 winners against Sochaux on Saturday, only on goals scored. St Etienne, who have not beaten Lyon in all competitions since 1994, suffered their third defeat of the season and dropped to 18th in the standings on three points. The hosts got off to a good start but proved too clumsy to catch the Lyon defence off guard, with France striker Bafetimbi Gomis trying his luck with a 30-metre drive that failed to surprise Hugo Lloris. Lyon put their grip on the game after the interval and Benzema, with a quickly taken shot, scored his fourth goal in the season in the 56th minute. St Etienne coach Laurent Roussey substituted midfielders Geoffrey Dernis and David Sauget by forwards Dimitri Payet and Ilan shortly after the hour, but to no effect. Earlier, Lille clinched their first win of the season when they came from a goal down to beat Girondins Bordeaux 2-1 at home. Last season's runners-up Bordeaux went ahead after 28 minutes with Argentine striker Fernando Cavenaghi netting his third goal of the season with a stunning 25-metre volley, but the hosts responded swiftly. Midfielder Michel Bastos levelled the tie just after the half hour by beating Ulrich Rame with a cross shot from close range after outpacing the Bordeaux defence. The northerners came out with all guns blazing in the second half and were rewarded for their efforts 14 minutes from time when midfielder Ludovic Obraniak found the net with a powerful shot from just inside the box. Lille, who have four points from four matches, climbed to 15th in the standings while Bordeaux dropped to seventh on six points. Elsewhere, Toulouse and Stade Rennes shared the points in a goalless stalemate.