Racing stun champions Toulon
Racing-Metro's centre Jamie Roberts runs with the ball during the French Top 14 rugby union match between Racing Metro 92 and RC Toulon on August 30, 2014, at the Yves du manoir Stadium in Colombes - by Thomas Samson
With every team in the league having won at least once following Saturday's earlier matches, the Parisians came into this encounter second bottom of the table but moved up to sixth.
Despite the defeat, European champions Toulon stayed top of the table, level on points with Toulouse, Clermont and Montpellier.
In a tight match, the breakthrough came after Toulon's South African hooker Craig Burden was sinbinned for a shoulder charge on a player without the ball.
It took Racing just two minutes to capitalise as their forwards rumbled towards the tryline before South African lock Francois van der Merwe dived over with the help of his pack.
Ireland fly-half Jonathan Sexton hit the extras but Toulon came roaring back before even Burden had rejoined his teammates.
James O'Connor broke from his own 22 and exchanged passes with Fijian Josua Tuisova and then beat the cover defence for pace on the outside before sliding into the corner.
Frederik Michalak, who had earlier missed a simple penalty, kicked the extras from wide out on the right.
The Parisians went into the break in front, though, as Sexton knocked over a penalty just after injuring his shoulder in a collision with Michalak.
Racing extended their lead shortly after the restart following a scything break from Samoan-born former All Black Casey Laulala.
Scrum-half Maxime Machenaud then picked the ball up from the back of a ruck, sold Rudi Wolf a dummy and went outside the sluggish Chris Masoe to score under the posts, converting his own try.
Almost immediately Michalak brought Toulon to within a converted try of the hosts with a penalty from the right.
Twice the champions knocked on the door in the closing stages but Racing's defence held firm.
Earlier, two second-half tries by New Zealand-born winger Alofa Alofa inspired La Rochelle to a memorable 37-25 victory over four-time European champions Toulouse.
Victory, with scrum-half Jean Audy contributing 22 points with the boot, was La Rochelle's first in the Top 14 this term following promotion.
It came a week after they were whipped 60-19 by Toulon, who ran in nine tries.
"This was a very disappointing performance," said Toulouse captain Thierry Dusautoir.
"We made a lot of mistakes in the first half but we made even more in the second, especially in the scrum.
"We need to learn from this and bounce back immediately," added the 32-year-old French skipper.
Toulouse burst out of the blocks with a try from former All Black hooker Corey Flynn, converted by his compatriot Luke McAlister.
However the hosts hit back almost immediately as their evergreen 38-year-old Fijian veteran Sireli Bobo went over.
Toulouse's second try came as Samoan lock Joe Tekori broke two tackles before scoring.
Four successful Audy penalties gave La Rochelle an early second-half lead, though, before McAlister's try put Toulouse 22-19 ahead.
However, the match really turned on its head when Flynn was sin-binned in the 56th minute for obstruction and La Rochelle scored 11 points in quick succession.
Audy created the first of Alofa's two tries with a superbly judged kick into the try area where the 23-year-old touched down after an athletic leap.
Alofa, born in New Zealand but who moved to Australia aged four with his family, rounded off a move that was started by the indefatigable Bobo inside his own 22.
The 2013 champions Castres finally got their first win of the season in a bonus-point 30-6 romp against Basques Bayonne.
There were also first wins of the season for newly-promoted Lyon, 24-6 against 1997 European champions Brive, Grenoble, 37-23 victors over Bordeaux-Begles, and Oyonnax, who ran in four tries to stun Stade Francais 33-6.
On Friday Montpellier had got the latest round of matches underway with a splendid 21-19 away victory over Clermont.