Grenoble recorded their fourth consecutive home win in the Top 14 after knocking over Perpignan 28-23 on Saturday.
Earlier, Toulon cruised back to the top of the tournament standings after brushing aside Biarritz 36-9 at Parc des Sports Aquilera.
Montpellier climbed to fourth in the standings with victory on the road over Racing Metro, while Stade Français recorded their first win outside the capital in two seasons by edging past Mont de Marsan.
In the late game, Toulouse needed a penalty try after the final hooter to sneak past Bordeaux-Bègles.
Aviron Bayonnais 37-16 SU Agen
Bayonne pivot Benjamin Boyet punished Agen's ill-discipline by kicking nine penalties to help carry his side to victory.
FC Grenoble 28-23 USA Perpignan
Grenoble made it back-to-back wins after getting the better of Racing last week.
The hosts dominated the first half but failed to build a lead and only had a 12-9 advantage at the break.
The game came to life in the second half however as Grenoble had to fight back after being behind at with 6 minutes left to play.
Aloisio Butonidualevu's try in the 78th minute proved decisive however.
Racing Metro 92 12-16 Montpellier HR
Racing Metro suffered two defeats on the trot after going down 16-12 at home to Montpellier on Saturday.
Les Heraultais are the big winners of round eight and will take plenty of momentum into the Heineken Cup.
Montpellier led 3-0 at half time before Alexandre Bias scored the winning on the hour mark.
Stade Montois 28-30 Stade Français Paris
Stade Français won the battle of the boot thanks to eight Jerome Porical penalties which helped them to their first victory on the road in two seasons.
But the Parisians were pushed all the way as Porical's winning kick came in the 74th minute.
Mont-de-Marsan's losing bonus-point finally gets them off the mark this season.
Union Bordeaux-Bègles 32-34 Stade Toulousain
Heartbreak for UBB, who, having led 29-10 saw Toulouse score three tries in the final quarter, including a penalty try in the sixth minute of time added-on to secure the points and go second in the standings.
A try from Australian winger Blair Connor and a double from Fijian star Metuisela Talebula had put Bordeaux in control.
But Toulouse's Fijian winger Timoci Matanavou grabbed two second-half tries to put the champions back on course before Bordeaux conceded a penalty try, with the home team buckling after a scrum set for a seventh time, five metres from their line.