Stade Français lost 23-6 at Bayonne, while Bordeaux-Bègles beat champions Toulon 28-23 in the French Top 14.
Bayonne scored three unanswered tries against the log-leaders, who suffered a second successive defeat having gone down to Oyonnax in round 17.
Bordeaux-Bègles overcame an 11-point deficit to stun Toulon at Stade Chaban-Delmas. Toulon were outplayed but the absence of several international players away on Six Nations duty, and injuries to other key individuals, including Bryan Habana, didn’t help their cause.
In other Top 14 matches, Peter Grant kicked a penalty and conversion as La Rochelle defeated Brive 19-12, Toby Flood contributed 18 points as Toulouse snuck past Lyon 23-20, Oyonnax beat Castres 23-13, Hendrik Roodt’s third-minute try helped hosts Grenoble sink Montpellier 20-18 and Clermont scored a late try to draw 13-13 with Racing Métro in Paris.
Round 18 results:
La Rochelle 19 Brive 12
Bordeaux 28 Toulon 23
Bayonne 23 Stade Français 6
Toulouse 23 Lyon 20
Oyonnax 23 Castres 13
Grenoble 20 Montpellier 18
Racing Métro 13 Clermont 13
Photo: Gaizka Iroz/Getty Images
