Jonathan Pitriopa's late goal sealed a comeback victory for Rennes that denied 10-man Troyes a second win of the Ligue 1 season.
Estac enjoyed the rare luxury of watching their Breton opponents chase the game for close to an hour, with Stephane Darbion doubling up after Benjamin Nivet headed the opener.
But Rennes pulled a goal back through Romain Alessandrini just after the break and Troyes soon wobbled, Julien Feret drawing the visitors level with an unstoppable drive nine minutes from time.
A point was within the hosts' grasp but they let it slip away at the death, Pitriopa breaking hearts at the Stade de l'Aube with a goal before Corentin Jean's unnecessary dismissal soon after his arrival as an 80th minute substitute.
Jean-Marc Furlan's men began brightly and Nivet lit the touchpaper on a frantic encounter in the 24th minute.
Chris Mavinga picked up the ball on the right wing before dispatching it to the far post, where Nivet stepped forward to nod it beyond Benoit Costil from close range.
Alessandrini came close to an equaliser but Yohann Thuram-Ulien tipped his strike away for a corner, and Troyes would extend their lead five minutes before the break.
Jean-Christophe Bahebeck wriggled free down the left, bamboozling Kevin Theophile-Catherine to pick out Darbion for an easy header.
The interval allowed Rennes to regroup and their response was swift, as Alessandrini took charge of proceedings to notch in the 48th minute.
Fabrice N'Sakala conceded a foul in a dangerous position and Alessandrini's free-kick took a convenient deflection to wrongfoot Thuram-Ulien and end up in the back of the net.
Mounir Obbadi was next to wheel away in celebration in the 77th minute, but the Troyes captain was offside when collecting N'Sakala's cross.
Feret fired a magnificent first-time shot into Thuram-Ulien's top corner four minutes later and Estac were losing control.
Furlan called retreat in a bid to cling onto a vital point but Rennes hit his players on the counter, Pitriopa racing on to Romain Danze's long ball to silence the home faithful with a cool finish.
It was already a lost cause but Jean added insult to injury with a careless tackle from behind on Danze that saw him pick up a second yellow card and his marching orders.
Rennes climb to seventh on the back of a third straight away win but Troyes remain eight points adrift of safety in 19th place.