O'Connor stars as Toulon, Montpellier, Racing make play-offs
A brace of tries in each half from O'Connor, capped 44 times by Australia, was matched by four more from his teammates as Quade Cooper, Charles Ollivon, Juan Martin Fernandez Lobbe and Eric Escande all crossed the whitewash.
Antoine Erbani grabbed a late consolation try for Agen, who had actually held a 6-0 lead for the first quarter after two early penalties.
The bonus-point victory put Toulon into second spot of the Top 14 on 77 points behind leaders Clermont, who play Stade Francais on Sunday.
"There were still some problems in our game but I don't know if it was the heat," said Toulon skipper and hooker Guilhem Guirado.
"Next week, we play Montpellier. It won't be a final but it will allow us to gauge ourselves against a team like that. It will be a big test."
Toulon were joined later Saturday in the six-team play-offs by Montpellier and Racing 92.
Montpellier, fresh from winning the European Challenge Cup last weekend, defeated Bordeaux-Begles 19-16 after Racing had crushed Pau 43-13.
Jake White's Montpellier have now won 11 of their last 12 games but were trailing 16-12 until South African hooker Bismarck Du Plessis grabbed his team's only try and the eighth of his Montpellier career.
Fellow South African, fly-half Demetri Catrakilis kicked the rest of Montpellier's points.
"After the European win, this game could have been a trap against Bordeaux who could have gone into the top six," said 2007 World Cup winner White.
"To win matches when you are in pain also shows the way you have progressed. In the past, this team could have lost that match."
Bordeaux's defeat had the added effect of promoting Castres into the sixth and final play-off spot with two games of the regular season left to play.
Castres scored 10 tries in a 67-20 rout of La Rochelle.
European Champions Cup runners-up Racing ran in six tries against Pau but the big-spending Paris side were hit by more injuries.
After Dan Carter (calf) and Maxime Machenaud (concussion) were already sidelined last week, Racing suffered three more worrying setbacks.
All Blacks back row forward Chris Masoe left the pitch in the 19th minute with a recurrence of the shoulder injury he suffered earlier in the campaign.
Fly-half Remi Tales picked up an ankle injury and was taken off at the interval while centre Casey Laulala took a hit on the right forearm he fractured two years ago.
Toulouse are in fifth place in the table and well-placed for a play-off spot after a 25-17 win at relegated Oyonnax.
Toulouse skipper Yoann Maestri saluted his team for the performance on Oyonnax's plastic pitch.
"We have never won here and this is a positive result because of the heat and artificial surface. Playing on it is a funny idea, the bounce is terrible," said Maestri.
Top 14 results:
Agen 13 Toulon 52
Brive 45 Grenoble 24
Castres 67 La Rochelle 20
Oyonnax 17 Toulouse 25
Racing 43 Pau 13
Montpellier 19 Bordeaux-Begles 16
Playing on Sunday, May 22:
Clermont v Stade Francais (14.15 GMT)
Top 14 table (played, won, drawn, lost, points for, points against, bonus points, total points):
Clermont 23 16 1 6 631 391 13 79 - qualified for play-offs
Toulon 24 15 0 9 699 407 17 77 - qualified for play-offs
Montpellier 24 17 0 7 662 508 9 77 - qualified for play-offs
Racing 92 24 16 1 7 544 483 7 73 - qualified for play-offs
Toulouse 24 14 2 8 605 368 10 70
Castres 24 13 0 11 590 462 11 63
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Bordeaux 24 13 2 9 515 452 6 62
Brive 24 12 1 11 487 501 7 57
La Rochelle 24 11 0 13 531 569 10 54
Grenoble 24 10 0 14 579 697 7 47
Pau 24 9 1 14 381 617 3 41
Stade Francais 23 8 0 15 491 534 5 37
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Oyonnax 24 5 0 19 390 799 2 22 - relegated
Agen 24 4 0 20 482 799 5 21 - relegated
Agence France-Presse