Marseille, who travel to Dutch side Twente Enschede for a UEFA Cup last-32 second leg tie on Thursday, allowed Lyon to open a six-point gap over Paris St Germain at the top after labouring to a goalless draw against lowly Le Mans last weekend.
"It will not help to cry over this," coach Eric Gerets told the club's website. "We missed an opportunity but ... it is not over.
"We are not dead yet. There was a time we were able to make forays into any defence. It has been a bit more difficult lately but it will come back."
Third-placed Marseille can exert pressure on the leaders before Lyon's home game against Stade Rennes, a team they have not beaten in the league at the Gerland stadium in the last three years, later on Sunday.
INJURY LAYOFF
Gerets should be able to call on Senegal striker Mamadou Niang, who has recently returned from a lengthy injury layoff.
Second-placed PSG and Girondins Bordeaux, in fifth, also drew last weekend.
PSG host troubled Nancy on Sunday, the same day as Bordeaux entertain Lorient. Both teams also feature in the UEFA Cup on Thursday, at VfL Wolfsburg and Galatasaray respectively.
Brazilian defender Ceara said the league was PSG's priority.
"Our first goal is the league and we will do whatever it takes to at least stay second," he said.
Fourth-placed Toulouse travel to AJ Auxerre on Saturday when victory would lift them to second, four points adrift of Lyon.
Sixth-placed Lille, nine points off the pace, visit neighbours Valenciennes on Saturday.
