A Brock James penalty in injury-time saw La Rochelle defeat Toulon 23-20 at the Stade Mayol to hit the summit of the Top 14.
Having started the weekend just a point behind Clermont Auvernge, Zack Holmes helped settle the nerves with a 14th minute penalty. Despit eseeing centre Levani Botia sin-binned on 19 minutes, La Rochelle saw Rattez score his opening try 10 minutes later.
But Toulon hit back just before the break as Jean Charles Orioli crossed the try-line two minutes before the break. Pierre Bernard converted and added a penalty two minutes after the break to level the scores at 10-10. Brock James and Bernard traded penalties before Rattez scored in the left corner.
Toulon battered the La Rochelle defence and with six minutes remaining were awarded a penalty try after the Toulon maul were pulled down as they marched towards the try-line.
In the final minute La Rochelle ravaged the Toulon pack on their own scrum to win the penalty which James calmly converted to seal victory for Patrice Collazo and Xavier Garbajosa's side.
Toulouse failed to take advantage of Toulon's slip up as they crashed to a 20-10 home defeat at the hands of Pau. It took the visitors just three minutes to open the scoring when Thomas Bianchin crossed to score.
When Ben Mowen was sin-binned 13 minutes in, Pau looked like they would escape the 10 minutes without conceding before Paul Perez popped up to jot down before he returned to the field.
Toby Flood converted but the return of Mowen saw Pau get back in front. Julien Fumat's try was converted by Slade and he added a penalty before half-time to give Pau a 17-7 lead.
Flood kicked Toulouse to within a converted try three minutes after the restart, but they failed to break down a dogged Pau defence, and saw winger Semi Kunatani sin-binned in the final minutes. Slade tagged on a penalty to seal the victory.
Grenoble grabbed a much-needed win in their fight for survival with a 44-22 victory over Stade Francais.
A dreadful start for Bernard Jackman's side saw Julien Arias and Jeremy Sinzelle cross for tries inside seven minutes and a 12-0 lead. Jonathan Wisniewski responded with two penalties for Grenoble who were dealt a blow when Fabrice Estebanez was sin-binned 20 minutes in.
But despite being a man down, they eneded the 10 minutes just two points down as Arnaud Heguy crossed for a try after a Jules Plisson penalty had stretched the Stade Francais lead.
Another Wisniewski penalty gave Grenoble a 16-15 lead going in at the break. Wisniewski added two penalties after half-time and Estebanez touched down to stretch their lead to 27-15 with 25 minutes to play. Pascal Pape saw yellow for the visitors and further tries from Xavier Mignot and Chris Farrell sealed the rout.
Castres remain in the top six after a 38-25 victory over Montpellier Herault. After Antoine Dupont's first minute try was converted, they faced an uphill task as Thomas Combezou was sin-binned after 11 minutes.
Montpellier hit back through Nemani Nadolo but two penalties from Castres' Julien Dumora helped them to a 13-8 lead on the half hour.
Paul Willemse's converted try swung the balance back in Montpellier's favour but a David Smith converted try saw them trail 20-15 the half-time. Dumora added a penalty after the break before Jody Jenneker was yellow for Castres.
But their defence was solid until his return and Dumora kept the scoreboard ticking over with another penalty after Jacques Du Plessis was sin-binned for Montpellier.
Willemse crossed again and Demetri Catrakilis converted to close the gap to 26-22 with a quarter remaining. Tries from Rory Kockott and Yannick Caballero rounded off the victory, and keep them within three points of Montpellier in the table.
An injury to Dan Carter marred Racing 92's 37-25 defeat to Lyon which saw the Paris club slump to 10th in the table.
It had looked promising when Teddy Thomas ran through to score four minutes in. Carter converted, but the sides were level by the 10th minute when Carl Fearns touched down, and Frederic Michalak converted.
He then cancelled out a Carter penalty three minutes later, on the quarter-hour. By this time new Munster signing James Hart had replaced Xavier Chauveau at scrum-half and Carter was replaced by Benjamin Dambielle.
Lyon saw Francisco Gomez Kodela sin-binned before the break and Hart and Dambielle kicked Racing to a 19-13 lead at the break. Hart kicked Racing nine points clear five minutes into the second-half before they fell apart.
Michalak kicked a penalty on 53 minutes and five minutes later Leone Nakarawa was sin-binned and Fearns grabbed his second before the hour. It got worse for Racing with Toby Arnold scoring converted tries either side of a third Hart penalty.
They currently have a 13 point breathing space between them and second-from bottom Grenoble. But continue as they are going and Racing could be in a dogfight for survival at the end of the season.
After Grenoble's win, it was crucial for Bayonne to keep get a win which they did, in a 33-23 victory over Brive. They were helped by the sin-binnng of two Brive players in the second-half with just three points separating the teams going into the final quarter.
Two Willie du Plessis penalties were cancelled out by two kicks from Brive's Gaetan Germain off the tee before Felix Le Bourhis touched down for the only try of the half for Bayonne on half-time. Du Plessis converted and kicked a penalty eight minutes into to the second-half for a 16-6 lead.
Brive struck back through Patrick-Albert Toetu, with Germain converting to close the gap to three points before the game changed on two yellow card decisions. First Dominiko Waqaniburotu saw yellow, 22 minutes from time, with du Plessis converting the resulting penalty.
Then, after Germain had narrowed the gap to three points with another penalty, Petrus Hauman saw yellow with 14 minutes remaining. Bayonne pressure resulted in a penalty try being awarded and Martin Bustos Moyano wrapped up the win with a try with 10 minutes remaining.
Clermont Auvergne could not retake top spot after a 23-23 draw at Bordeaux Begles. New Zealander Stephen Brett kicked a penalty in second-half injury-time to salvage the draw which Bordeaux thought they had done just enough to win.
Converted tries from Luke Braid and Yann Lesgourgues saw Bordeaux lead 14-3 at the break. Clermont struck back after half-time through a Benson Stanley try, but Simon Hickey who converted the two earlier tries kicked a penalty to stretch Bordeaux's lead out to 17-10.
Clermont hit back with a half hour remaining, as Sitaleki Timani's try was converted by Brett. Hickey and Brett traded penatlies before replacement Ian Madigan thought he had sealed victory for Bordeaux with a penalty, seven minutes from time. Up stepped Brett in injury-time to level the game, which saw Clermont relinquish first place after La Rochelle defeated Toulon on Saturday.