The fifth-placed hosts, meanwhile, lost their last outing 1-0 at home to new leaders Lille, finally breaking a seven-match unbeaten streak.
A dramatic final twist in Lorient's action-packed 3-2 win against PSG last weekend saw Nigerian striker Terem Moffi stride clear of the Parisians' defence as Mauricio Pochettino's side pushed for a late winning goal, to settle the game in style - against all the pre-match odds.
Remarkably, that goal was their second injury-time winner in just a matter of days - after they defeated fellow strugglers Dijon by the same scoreline earlier last week - and served to elevate Christophe Pelissier's men above the Burgundy outfit. Having returned to action for the first time since a devastating COVID-19 outbreak, Lorient now seem to have a new lease of life.
Up to a still-precarious 18th place, but glowing from their limelight-grabbing success - achieved despite the concession of two penalties, both converted by Neymar - Les Merlus are now set on inching out of the drop zone by taking a first step towards improving a woeful away record.
Lorient have proved easy meat for opponents when on the road this season, having posted only two draws and just one win in 10 trips so far. Currently on a six-match winless streak away, they have failed to win outside of their Breton base since October, against Reims.
Certainly, Pelissier will hope that his side's recent burst of goals can continue on Wednesday, as their forward line had previously underwhelmed this season. Only Yoane Wissa, match-winning hero Moffi and Pierre-Yves Hamel have made contributions of note so far, netting six, five and four times respectively.
Despite dominating possession at Roazhon Park last Saturday, Rennes were unable to find an equaliser to Jonathan David's early goal for Ligue 1 leaders Lille, who subsequently deposed PSG at the top of the table.
It brought to an end a stabilising spell of form for Julien Stephan's side, as they had turned their fortunes around since an abysmal winless run in late autumn. Nonetheless, with a game in hand, they remain within sight of the Champions League qualification places, but will need all their main men fully firing in the upcoming weeks.
One such star, France international Eduardo Camavinga, claimed in recent days to be "100% focused on the club" despite a change of agent to Gareth Bale's media mouthpiece Jonathan Barnett. Though Camavinga has a contract which runs until June 2022, he has scored only once and provided just two assists in 23 appearances at club level during the 2020-21 campaign, leading to talk of being distracted by rumours of a move to Real Madrid.
The gifted midfielder can prove his stated dedication in midweek, by helping Rennes to improve a record of just five wins and four losses from 11 home contests in Ligue 1 this term.
His side emerged victorious when these two sides last met, at Stade du Moustoir in December. That 3-0 win for Les Rouge et Noir should serve as a template for bringing a rejuvenated Lorient XI back down to earth with a bang.
Rennes Ligue 1 form: WWDDWL
Lorient Ligue 1 form: LDLLWW
Most of Lorient's contingent affected by COVID-19 returned to action last week, but Paul Nardi and Vincent Le Goff are still recovering from the after-effects of the virus, so their involvement on Wednesday is uncertain.
As Christophe Pelissier must assess whether his returning players are ready for another 90 minutes so soon, he may rotate - with Trevoh Chalobah and Terem Moffi both in contention to make the starting lineup.
Rennes possible starting lineup:
Salin; Traore, Nyamsi, Aguerd, Maouassa; Truffert, Nzonzi, Camavinga, Doku; Grenier; Terrier
Lorient possible starting lineup:
Dreyer; Delaplace, Laporte, Gravillon, Morel; Lauriente, Le Fee, Chalobah, Wissa; Hamel, Moffi
We say: Rennes 2-1 Lorient
Rennes can prove their relative class to break the Lorient spell this week, as Stephan's men boast enough ability to avoid faltering at home against lowly opposition.
The visitors' extraordinary trend of late winners must come to an end, with a long, hard-fought slog against relegation still in prospect this spring.