Stade FranÃ§ais, Perpignan, Bayonne and Toulon all held on by the skin of their teeth for victories in the Top 14 on Wednesday.
Six of the seven games played saw the losing team get a losing bonus-point.
Perpignan needed a controversial try to get past Biarritz while Stade FranÃ§ais almost threw away a 20-point lead and needed the help of the TMO to beat Castres and retake the provisional lead in the standings
Toulon were unable to score a try in La Rochelle but three drop goals from Jonny Wilkinson were enough for a narrow win.
Montpellier snuck past Toulouse thanks to a missed conversion after the hooter to win by a single point.
Elsewhere, Bayonne edged past Brive by the narrowest of margins while Bourgoin got their first win of the season against Agen.
In the late game, the Racing-Metro pack dominated a below-strength Clermont team in Paris.
Montpellier 22-21 Toulouse
Perpignan 17-12 Biarritz
Bayonne 19-18 Brive
La Rochelle 13-15 Toulon
Bourgoin 22-15 Agen
Stade FranÃ§ais 40-34 Castres
Racing-Metro 28-17 Clermont.
1 Stade FranÃ§ais 13
2 Bayonne 13
3 Montpellier 13
4 Racing MÃ©tro 12
5 Toulouse 11
6 Clermont 11
7 Castres 10
8 Toulon 10
9 La Rochelle 9
10 Perpignan 8
11 Biarritz 6
12 Brive 6
13 Agen 5
14 Bourgoin 4
USA Perpignan 17-12 Biarritz Olympique
Stade AimÃ© Giral, Perpignan
Those hoping for an open match of rugby were sorely disappointed as two teams under pressure chose to keep it tight. There was no lack of big hits though as the respective packs smashed each other to bits.
A massive defensive effort from Biarritz earned them a 9-7 lead at half-time with three penalties coming from the boot of scrum-half Dimitri Yachvili.
Perpignan's only point in the first half came in controversial circumstances after scrum-half Kevin Boulogne took a quick penalty on the 22 to score untouched while the Biarritz players were distracted by the presence of the medical support on the field.
The turning point of the game came when Biarritz skipper JÃ©rÃ´me Thion was sent to the sin bin following a mass punch-up soon after the break. A man down, the visitors defence finally cracked as Perpignan prop Guilhem Guirado crashed over.
20-year-old Perpignan fly-half Gilles Bosch added a drop goal in the 66th minute to seal the deal for the Catalans.
Stade FranÃ§ais Paris 40-34 Castres Olympique
Stade CharlÃ©ty, Paris
It was high drama in Paris as it took the TMO an eternity to decide who would win the game after a pile of Castres bodies had crashed over the Stade tryline after the final hooter.
The final verdict was that the ball was stuck onto a Parisian boot, much to the relief of the home team, who had fallen apart in the second half.
A try festival saw eight five-pointers being scored. Stade led 37-17 at half time before nearly throwing the game away.
An error-riddled start for the visitors allowed Stade to score five first-half tries (Dimitri Szarzewski, Sergio Parisse 2 and Ollie Phillips 2). Samoan lock Iosefa Tekori scored for Castres.
The second half however was all Castres as a yellow card for Stade loose forward Juan Leguizamon helped the visitors fight back as flank Ibrahim Diarra and centre Yoan Audrin touched down.
Castres were missing the duel kicking threat of full-back Romain Teulet and Cameron McIntyre, who were both rested. Fijian Sermaia BaÃ¯ took over at fly-half and kicked four penalties and a conversion.
Stade Rochelais Atlantique 13-15 RC Toulon
Stade Marcel Deflandre, La Rochelle
Once again Toulon failed to impose themselves and failed to cross the whitewash.
Two penalties and two drop goals from Jonny Wilkinson gave the visitors a 12-0 lead at the break. It seemed harsh on the more enterprising hosts, but RCT impressed with their clinical ability to add points whenever they got within striking range.
A third drop, from 40m out gave Toulon a 15-6 lead going into the last quarter.
Les Maritimes will be frustrated by the number of opportunities they wasted but they did manage the only try of the game when Fijian wing Norman Ligairi touched down in the dying minutes.
Aviron Bayonnais 19-18 CA Brive CorrÃ¨ze
Stade Jean Dauger, Bayonne
The crowd at Jean Dauger were treated to a real ding-dong battle. Brive led for much of the game and would have come out victorious but for a superb performance from Bayonne scrum-half Julien Audy, who scored all of his team's points.
Early tries to fly-half Mathieu BÃ©lie and centre Jamie Noon helped Brive to a 12-0 lead but the hosts came back strong as Audy scored a try and two penalties to reduce the gap to 15-13 at half-time.
Brive's poor discipline in the second half allowed Audy to give his side a 19-18 lead going into the final quarter when the Basque pack ensured the grandstand finish would go the hosts' way.
CS Bourgoin-Jallieu 22-15 SU Agen
Stade Pierre Rajon, Bourgoin
A vital first win for Bourgoin against a potential rival in the relegation battle.
Bourgoin led 19-6 at half-time after they scored their first try of the season through flank Yann Labrit.
The hosts, who had easily controlled the first half, were pushed by an Agen fight-back in the second period but held on for four invaluable points.
South African fly-half Conrad Barnard kicked all of Agen's points.
Montpellier HR 22-21 Stade Toulousain
Stade Yves Du Manoir, Montpellier
Read the match report here
Racing-MÃ©tro 28-17 ASM Clermont Auvergne
Stade Yves Du Manoir - Colombes (Paris)
Read the match report here