Castres, Stade Francais, Lyon, Bordeaux-Begles and Agen were the winners on a busy day of Top 14 action.
Stade Francais' reign as European Challenge Cup holders is over after defeat to Pau, who joined Newcastle Falcons in the semi-finals.
Heyneke Meyer has returned to coaching, taking the role at Stade Francais as the Top 14 club look to stave off relegation.
Stade Francais' five-match losing run in the Top 14 came to an end on Sunday, while Toulouse missed the chance to take second.
Ben Botica ensured Oyonnax built on their win at Clermont with another victory that boosted their unlikely Top14 survival bid.