A 26-10 defeat to Biarritz may have cost Toulouse dear, with Perpignan, Castres and Clermont all winning in the Top 14 on Saturday.
Perpignan's glittering 44-23 success over Stade Français both put them top and effectively ended the Parisians' season, while Clermont and Castres' victories mean there are now three teams tussling over the top two spots and automatic qualification for the semi-finals and a rest week to go with it.
Racing Metro put daylight between the top six and the chasers with a 25-18 win at home to Brive, while at the bottom, Montauban's 26-12 win at Albi lifts them out of the drop zone to be replaced by Montpellier, victims of a 41-3 thrashing by Clermont.
Results, week 23:
Friday March 26:
Bourgoin 9-13 Toulon
Saturday March 27:
Racing Metro 25-18 Brive
Castres 26-10 Bayonne
Clermont 41-3 Montpellier
Albi 12-26 Montauban
Perpignan 44-23 Stade Français
Biarritz 26-10 Toulouse
1 Perpignan 71
2 Castres 71
3 Clermont 70
4 Toulon 67
5 Toulouse 65
6 Racing-Métro 92 59
7 Biarritz 52
8 Brive 52
9 Stade Français 49
10 Bourgoin 45
11 Montauban 45
12 Bayonne 43
13 Montpellier 42
14 Albi 20
Racing Metro 92 Paris 25-18 CA Brive-Corrèze
Somehow Racing emerged from the first half in the lead, after having enjoyed just 31 per cent of the ball. But Brive's errors an the monster boot of Francois Steyn ensured the Parisians went in 12-8 to the good at the break.
The second half was different as soon as Sebastian Chabal had crashed over for the home side's first try of the match three minutes into it.
A penalty from Andrew Mehrtens followed and then on the hour mark Sereli Bobo hared down the right wing for his side's second score to make it 25-8.
Brive fought back, with a try from Jamie Noon to show for their efforts and Alexis Palisson's late penalty gave Brive a bonus point, but it all came too late for the Brivistes, whose season is now all but anticlimax unless a French side wins the Heineken Cup
Castres Olympique 26-10 Aviron Bayonnais
Table-topping Castres face a nasty run-in and this was their last 'easy' match before clashes with Toulouse, Perpignan and Clermont, so a win was non-negotiable, bonus point preferable.
Bayonne made it easy for them with an indisciplined display but Castres made harder work of it. It was 10-10 at the break, with Mathieu Bonello's try, Romain Teulet's conversion and Cameron McIntyre's drop goal for Castres cancelled out by Nicolas Laffite's try and Cedric Garcia's conversion and penalty for the visitors.
The second half was much better from the home side though and once Joe Tekori had crashed over for his side's second try near the hour mark, the result was never in doubt.
ASM Clermont Auvergne 41-3 Montpellier HRC
Clermont stay third after this victory but you'd not bet against them finishing top of the table once all 26 weeks are done and dusted.
Penalties were dismissed as just something other teams do to get points for much of the first half until Brock James' effort three minutes before the break, but the frustrated home side led only 10-3 at half-time, with Marius Joubert's try the difference.
The second half was different. Anthony Floch raced over for a score and then the floodgates opened in the final quarter, with Davit Zirakashvili, James, Elvis Vermeulen and Benoit Cabello all doting down.
USA Perpignan 44-23 Stade Français
The champions were just brilliant. Seven tries they scored in a feast of attacking rugby which no team could have done anything about, never mind an ailing former champion. It was just one of those days.
Perpignan led 24-9 by the break, but four tries to nil. Jerome Porical, Farid Sid, Gerrie Britz and David Marty all scored, with Porical converting two, while Lionel Beauxis' boot - two penalties and a drop goal - just about kept the visitors in touch.
Within two minutes of the second half restarting Porical had crossed for his second and put the outcome of the game beyond doubt.
There were further tries for Marius Tincu and Nicolas Durand, while Stade finally came to life towards the end and Mirco Bergamasco and James Haskell both dotted down to give some respectability to the scoreline. By that point though, the party in the Aimé-Giral stands was already in full swing, celebrating what must be the team performance of the season.
SCA Albi 12-26 Montauban
Montauban will probably feel relieved they won and climbed out of the bottom two but if relegation is tight at the end and Montauban do go down they will look back at this and rue not getting the bonus point.
They led 16-0 at the break, with a try by Brive Mach supplemented by Cedric Rosalen's conversion and trio of penalties.
It was 26-0 five minutes into the second half, with Rosalen landing a fourth kick and then Albert Figueiredo picking off a stray Albi pass for the second try.
But instead of kicking on and thrashing their hosts, Montauban sat back and shipped tries to Vincent Clement and Pierre Lakafia. No difference to the result, but how costly could the missed bonus point be?
Biarritz Olympique 26-10 Stade Toulousain
A flicker of hope remains for Biarritz's season after this win, but they need Racing Metro to slip up badly if they are to claim a play-off spot.
This was a pulsating clash at the Anoeta, in which Toulouse were superb in patches but dreadful in others and now will have to rely on other results going their way if they are to finish in the top two.
The indiscipline shown by the visitors, which had Guy Noves apoplectic at one stage, allowed Dimitri Yachvili to punish them with six penalties, while Damien Traille landed as sweet a drop goal as you could ask for.
Toulouse scored the only try of the opening 79 minutes with a brilliant backs move that culminated in Maxime Medard going over in the corner but they could muster little else in the way of tryline action.
Instead it was left to the hosts to raise the roof in the final minute, with Taku Ngwenya breaking from turnover ball and Traille finishing off in the corner.