Late drama in Lille saw Frédéric Michalak kick a winning penalty for Toulon against Racing, securing a 21-20 victory.
Dan Carter looked to have won the match for Racing after his late converted try put them ahead in the game for the first time, following Maxime Machenaud's quick thinking with a tapped penalty.
But Michalak had other ideas, knocking over the three-pointer from 35 metres out with time up on the clock for Toulon's 12th win of the season, to move them a point behind Clermont at the top, who play on Sunday.
Michalak's excellent strike opened the scoring with a long-range penalty, won at the scrum by Toulon's pack after five minutes at the Stade Pierre Mauroy.
Carter in turn levelled up the scores before Toulon struck with the game's first try.
Jean Charles Orioli leapt out of the line for a timely interception, before the hooker released Delon Armitage for a 60-metre run to the line, scoring in the corner to make it 8-3.
Michalak couldn't convert but the former France fly-half was on hand with a penalty from 40 metres out to increase the European champions' lead.
Racing came close to the next try, denied by the TMO, and more pressure before the interval went unrewarded as Toulon took an 11-3 advantage into half-time.
Charles Ollivon's carrying was a real weapon for Toulon and it was the number eight's work off the back of the scrum which led to their second try after 50 minutes.
Skipping past two defenders Ollivon did well to then release young Toulon centre Théo Belan, his score and the resulting conversion from Michalak making it 18-3.
Racing at this point looked adrift but a second Carter penalty helped reduce the deficit a little as they tried to chase down Toulon's lead.
At last they managed to crack the defence with a try on 73 minutes from Wenceslas Lauret, converted by Carter, as the flanker finished off a long phase of pressure.
The late drama then followed, Carter crossing after Machenaud's tapped penalty to put Racing ahead for the first time after the conversion at 18-20, before Michalak countered by knocking over the winning points with his third penalty.
Tries: Lauret, Carter
Cons: Carter 2
Pens: Carter 2
Tries: Armitage, Belan
Pens: Michalak 3
Racing 92: 15 Brice Dulin, 14 Juan Imhoff, 13 Henry Chavancy, 12 Dan Carter, 11 Marc Andreu, 10 Rémi Talès, 9 Maxime Machenaud, 8 Chris Masoe, 7 Bernard le Roux, 6 Wenceslas Lauret, 5 Francois van der Merwe, 4 Luke Charteris, 3 Luc Ducalcon, 2 Dimitri Szarzewski, 1 Julien Brugnaut
Replacements: 16 Camille Chat, 17 Khatchik Vartanov, 18 Manuel Carizza, 19 Antonie Claassen, 20 Xavier Chauveau, 21 Johan Goosen, 22 Albert Vulivuli, 23 Martin Castrogiovanni
Toulon: 15 Quade Cooper, 14 Delon Armitage, 13 Théo Belan, 12 Tom Taylor, 11 James O'Connor, 10 Frédéric Michalak, 9 Éric Escande, 8 Charles Ollivon, 7 Gregory Annetta, 6 Virgile Bruni, 5 Kote Mikautadze, 4 Thibault Lassalle, 3 Manasa Saulo Romumu, 2 Jean Charles Orioli, 1 Alexandre Menini
Replacements: 16 Iuri Natriashvili, 17 Florian Fresia, 18 Andrew Cramond, 19 Jocelino Suta, 20 Kylian Jaminet, 21 Bryan Habana, 22 Anthony Meric, 23 Mohamed Boughanmi
Referee: Laurent Cardona