Christophe Pelissier's side slipped back into the relegation zone despite holding Nice to a 1-1 draw last Friday, while Rennes lost 1-0 to Marseille, their rivals for a European place, two days later.
Match preview
In the club's first top-flight season for a decade, Auxerre have hopped on either side of the perforated line - with the drop zone now including four teams instead of the usual three this year ahead of a restructuring next term.
Pelissier endured a seven-match losing glut shortly after his appointment in October but has since steered Auxerre to a five-game unbeaten run in Ligue 1 - the club's longest lossless sequence in the top flight since 2011.
Gauthier Hein put Auxerre ahead against a similarly in-form Nice side last Friday before Gaetan Laborde levelled - but Brest's victory against fellow strugglers Strasbourg the same weekend nudged the Burgundy outfit into 17th on goal difference.
No player in Auxerre's squad can boast more than three league goals this season, with chances just as hard to come by; only Ajaccio have attempted fewer shots on target.
At the other end of the pitch, January arrival Ionut Radu has been instrumental to Auxerre's uptick, saving a penalty from Laborde on Friday in another crucial display as the former Cremonese goalkeeper banishes memories of Benoit Costil's calamitous six months between the sticks in the first half of the season.
Pelissier has lost all nine of his managerial meetings against Bruno Genesio, comfortably the worst head-to-head return in his coaching career and unsurprisingly the best record for the current Rennes manager who certainly lives up to his (otherwise ironic) nickname of 'Pep' in this particular matchup.
Genesio has not quite been able to replicate Pep Guardiola's best work against the other managers he has faced recently, with Rennes losing five of their last six away matches.
The Brittany team's struggles since the turn of the year have coincided with the season-ending injury to Martin Terrier; Rennes have taken 12 points from nine league games since the influential forward ruptured his cruciate ligament in January, a tally half the division can match or better in this same time frame.
Nevertheless, Rennes remain fifth, five points behind third-placed Monaco in the final Champions League qualification spot which the club are still chasing.
Rennes' biggest victory of the season came in their last meeting with Auxerre when Genesio's side romped to a 5-0 win in September at Roazhon Park - regrettably for the Burgundy outfit, Auxerre have lost by the same five-goal margin on two other occasions this season.
Auxerre Ligue 1 form:
L
D
D
W
W
D
Auxerre form (all competitions):
D
L
D
W
W
D
Rennes Ligue 1 form:
W
L
L
W
W
L
Rennes form (all competitions):
L
L
W
L
W
L
Team News
Auxerre's joint-top scorer Nuno da Costa - one of three players with that pitiful tally of three goals - has missed the last two games with a hamstring injury which could sideline him alongside Hamza Sakhi (ankle) again this weekend.
As he nears the conclusion of a lengthy recovery from a knee injury, Theo Pellenard made his first competitive appearance of the season for Auxerre's B team last weekend but may not be rushed back to the senior side as soon as Saturday.
While Kays Ruiz-Atil is a doubt with illness, Elisha Owusu has not featured since arriving from Gent in January and is not expected to play a significant role in the remainder of the season as he nurses an Achilles tendon problem.
Xeka (ankle) and Lorenz Assignon (knee) join Terrier as long-term absentees in a busy treatment room at Rennes.
Captain Hamari Traore has been sidelined since January with a calf problem that also clouds his availability this weekend, while Flavien Tait is a doubt with an ankle issue.
After the opening half of his season was hampered by injury, Warmed Omari had returned to the heart of Rennes' defence but is set to sit out the trip to Burgundy following an accumulation of yellow cards.
The fleet-footed young forward Jeremy Doku was forced off with an injury in the first half of Rennes' defeat to Marseille and is a doubt this weekend.
Auxerre possible starting lineup:
Radu; I Toure, Jubal, Raveloson; Zedadka, B Toure, Massengo, Mensah; Dembele, Albline, Hein
Rennes possible starting lineup:
Mandanda; Spence, Rodon, Theate, Truffert; Doue, Santamaria, Bourigeaud, Toko Ekambi; Gouiri, Kalimuendo