Lyon boss Rudi Garcia urged his players and the team's supporters to stay calm as the side attempts to sustain a challenge for the 2021 French title.
Victory at the Stade Francis-Le Blé will take them on to 55 points and ahead of pacesetters Lille on goal difference.
Following Thursday night's exploits in the Europa League, Lille take on Lorient on Sunday afternoon.
Second-placed Paris Saint-Germain entertain fourth-placed Monaco on Sunday night at the Parc des Princes.
With six points separating the top four teams; questions over Lyon's resilience were raised after they slumped to a 2-1 defeat at home on 13 February to Montpellier.
It was their first loss in 16 games since they went down to the same opponents on 15 September 2020.
"We've only lost three times this season," Garcia said.ahead of the game in Brittany.
"There is no reason to panic and it's a good sign if the substitutes are pushing for a chance to start matches ... because that's what I expect from them.
"But I can also show the starting eleven that they have done so well so far that they deserve to continue. Of course no position is guaranteed."
Brest, who held leaders Lille to a 0-0 draw last weekend at the Stade Pierre Mauroy, crave more modestly than titles and places in the Champions League. A win for the hosts will consolidate their position in mid-table with 34 points from their 26 encounters.
"Lyon have been on a good run," said Brest coach Olivier Dall'Oglio. "They're coming up against teams who are setting up defensively against them and hoping to hit them on the counter.
"We were good against Lille defensively. We didn't make any mistakes and we'll have to remain solid against Lyon because they can hurt you at any moment either collectively or with individual moments of brilliance," Dall'Oglio added.