Bafetimbi Gomis fired Lyon into the top three of Ligue 1 with the only goal of the game against Brest at the Stade Gerland.
Gomis struck just before the hour mark to end Lyon's three-game winless run and keep them in touch with the leaders.
While it was hardly the most convincing performance from Remi Garde's side, against a Brest team that has now lost all five of their away games, it was a much-needed success ahead of next weekend's anticipated trip to leaders Marseille.
OL were unsurprisingly dominant in the opening half but their failure to score before the break gave Brest some hope of a first ever Ligue 1 win over their hosts in seven attempts.
The visitors had to ride their luck early on as goalkeeper Alexis Thebaux made a reaction save after Gomis and Lisandro Lopez appeared to get touches on a Steed Malbranque free-kick.
Jimmy Briand then shot against the crossbar from close range after Thebaux pushed Dejan Lovren's firm header away.
Brest were unconvincing and Ahmed Kantari cheaply gave the ball away only for Alexandre Lacazette to shoot straight at Thebaux from 30 yards.
After being second best, Brest could have stolen the lead just before the interval but Eden Ben Basat completely missed the ball after Bernard Mendy and Ousmane Coulibaly had done well to create the chance.
Benoit Lesoimier could still have bundled the ball home at the back post but was off target.
The away side got a further chance to go ahead after the break but Ben Basat took too long to pull the trigger and Lovren made a last-ditch tackle.
Minutes later Lyon finally grabbed made their dominance count on the scoreboard.
The impressive Malbranque played an inch-perfect pass in behind the defence and Gomis lost his marker Paul Baysse before lobbing the ball over Thebaux.
It proved enough to secure the win as Thebaux made a smothering block in front of Lopez before a last-ditch Johan Martial tackle prevented the Argentinian from adding to the score late on.