Oyonnax kept their slim Top 14 survival hopes alive with a second consecutive victory, while struggling Clermont landed a precious win of their own.
Basement side Oyonnax saw off relegation rivals Stade Francais 33-27 to move within four points of 13th-placed Brive, having ended a 14-match winless run at Clermont last week.
Ben Botica was the star of the show at Stade Charles Mathon, kicking three early penalties and then scoring Oyonnax's fourth try of the first half in the 37th minute.
Daniel Ikpefan and Hikawera Elliot had earlier gone over, with Willem Alberts and a penalty try getting the Paris outfit up and running, as the hosts took a 28-15 lead into the break.
Although Ikpefan soon scored again, the tables started to turn and Oyonnax were relieved to hear the final whistle after tries from Julien Arias and Marvin O'Connor significantly narrowed what had appeared to be a comfortable winning margin.
Clermont responded well to defeat against Oyonnax - their sixth in a row - as they dealt La Rochelle's play-off chances a blow in a 21-17 win.
La Rochelle had fallen out of the top six with back-to-back losses and a third in succession leaves Patrice Collazo and Xavier Garbajosa's men in seventh.
Peceli Yato scored the only try of the first half for Clermont, before Arthur Iturria added his name to the scoresheet.
Greig Laidlaw and Alexi Bales had traded penalties throughout - a total of seven by the hour-mark - but La Rochelle's first try did not come until Gregory Alldritt went over in the final seconds.