Second-placed Lyon are now one point adrift of Bordeaux, who appeared weary and clueless against Lille and conceded two goals from midfielders Yohan Cabaye and Florent Balmont.
"It's nice to take points at home but if you take no point away, it is very hard to stay top," Bordeaux coach Laurent Blanc told reporters.
At their Gerland stadium, Lyon failed to make the most of Bordeaux's slip-up.
They finally set to take all three points to move past Bordeaux but Toulalan netted his own goal from a packed goal mouth three minutes into injury time.
Both sides were quick off the mark.
Miralem Pjanic volleyed home after only three minutes following a bad clearance by the Marseille defence. The visitors, however, hit back nine minutes later when Stephane M'Bia deflected a Souleymane Diawara header past Lyon keeper Hugo Lloris.
Lyon reacted swiftly. Sidney Govou slalomed through the Marseille half before unleashing a curling shot past Steve Mandanda to make it 2-1.
LOPEZ DOUBLE
Didier Deschamps's side did not make the most of their posession until just before half-time when Lloris, who had been brilliant in a 1-1 Champions League draw against Liverpool on Wednesday, failed to handle a Bruno Cheyrou 25-metre strike.
Marseille took the lead two minutes into the second half, with Ivory Coast striker Bakari Kone spinning the ball past Lloris froma Fabrice Abriel cross.
Brazilian striker Brandao added a fourth from close range but the goal prompted Lisandro Lopez into action.
The Argentine striker reduced the gap on 81 minutes by flicking the ball past Mandanda after out-muscling the Marseille defence and converted a penalty three minutes later after a Gabriel Heinze handball in the box.
Brazilian winger Michel Bastos triggered a huge roar in the Gerland stands when he scored after being set up perfectly by Pjanic before Toulalan silenced his own crowd seconds before the final whistle.
Marseille still trail Bordeaux by six points but they have a game in hand.
"Well, scoring five goals to snatch only a point, it's a bit frustrating," Marseille midfielder Fabrice Abriel told French TV channel Canal Plus.
"There were a lot of chances, a lot of good play and we provided the crowd with a good show but it's a bad result for both teams," said OL defender Aly Cissokho.
Earlier, French internationals Moussa Sissoko and Andre-Pierre Gignac found the back of the net to help Toulouse beat Stade Rennes 3-2.
