The visitors are yet to win on the road this term, while the hosts have failed to win each of their last three home games, conceding nine goals in the process.
Match preview
Brest saw their winless Ligue 1 run extended to four matches last weekend, but there were plenty of positives to take away from their slender 1-0 loss away at reigning champions Paris Saint-Germain.
South American stars Lionel Messi and Neymar combined for the game's only goal with the former setting up the latter on the half-hour mark. Brest frustrated the hosts for large spells and they had the chance to equalise in the 70th minute, but Islam Slimani's penalty kick was saved by Gianluigi Donnarumma.
Michel Der Zakarian's side remain in the relegation zone with just five points from their opening seven matches, but a favourable-looking set of fixtures are on the horizon, with back-to-back games against two newly-promoted teams followed by a run of six matches against sides who finished outside of last season's top four.
Brest have won four of their five Ligue 1 home games against newly-promoted teams since they returned to the top flight four years ago, and they have also won their last two encounters with Ajaccio by a 2-0 scoreline, so they will fancy their chances of success on Sunday.
Competing in Ligue 1 for the first time since 2013-14, Ajaccio are one of only two teams who are yet to win any of their opening seven games of the new season.
After playing out a goalless draw at home to Lens in their second top-flight match since securing promotion, the Bears have since suffered five successive defeats, including the 1-0 loss at home to Nice last weekend.
Olivier Pantaloni will not be panicking just yet, but his side are now five points adrift from safety and have fixtures against table toppers PSG and Marseille coming up before the World Cup in November.
Ajaccio have lost all three away games so far this season, but they have won two of their last three visits to Brest, both of which in Ligue 2 including the 2-1 victory in January 2018.
Brest Ligue 1 form:
Ajaccio Ligue 1 form:
Team News
Brest midfielder Youcef Belaili will serve a one-match suspension due to an accumulation of yellow cards, while Jeremy Le Douaron (groin), Steve Mounie (heel) and Romain Del Castillo (hamstring) all remain sidelined with injuries.
After operating with a back five against PSG, Der Zakarian may decide to revert to a four-man defence, which could see centre-back Christophe Herelle drop out of the first XI and replaced by winger Mathias Pereira Lage.
Pierre Lees-Melou, Mahdi Camara and Haris Belkebla are set to continue in centre-midfield, while striker Islam Slimani could retain his place in attack.
As for Ajaccio, they will have to cope without Kevin Spadanuda, Yanis Cimignani and Fernand Mayembo due to injury.
Pantaloni is set to continue with a flat 4-4-2 formation which he has used throughout this season, with Oumar Gonzalez expected to return to centre-back after serving a one-match ban last weekend.
Mounaim El Idrissy, who has scored one of Ajaccio's three league goals so far this term, could be recalled to the first XI at the expense of either Yoann Touzghar and Romain Hamouma.
Brest possible starting lineup:
Bizot; Fadiga, Dari, Chardonnet, Brassier; Belkebla, Camara, Lees-Melou; Honorat, Slimani, Lage
Ajaccio possible starting lineup:
Leroy; Youssouf, Gonzalez, Vidal, Ismael; Bayala, Mangani, Marchetti, Spadanuda; El Idrissy, Hamouma
We say: Brest 2-1 Ajaccio
Both sides will view this fixture as a good opportunity to turn their fortunes around and begin to put a positive run of form together.
After Brest showed promising signs of improvement against PSG, we can see the hosts coming out on top this weekend.