After a run of six defeats in their last seven Top 14 games, Simon Mannix has stepped down as Pau's sporting director.
Sofiane Guitoune's 77th-minute try carried Toulouse past Clermont Auvergne as the top two in the table served up a Sunday treat.
La Rochelle put Pau to the sword and Castres also enhanced their chances of reaching the play-offs with a win in Bordeaux.
Clermont Auvergne had to settle for a draw against Racing 92, while Lyon held on to beat Pau in a thrilling day of Top 14 action.
Toulon may have been at a numerical disadvantage for most of the second half but they still managed to defeat Top 14 leaders Toulouse.
Paul O'Connell has been linked with Toulon, but the outgoing Stade Francais forwards coach says he will not join another club next season.
Toulouse are now unbeaten in 14 Top 14 matches after grinding it out at La Rochelle, while Racing 92 got the better of Bordeaux.
Tries from Carl Fearns, Mickael Ivaldi and Thibaut Regard helped Lyon get back to winning ways in Saturday's Top 14 action.
The Top 14's leading two both won on Sunday, but it was Toulouse's bonus-point success that grabbed the attention.
There were big wins for 2017-18 Top 14 finalists Castres and Montpellier on Saturday, with Benjamin Urdapilleta inspiring.