Montferrand produced a superb comeback to earn a Parker Pen Challenge Cup quarter-final berth against Saracens with a 25-13 victory against the Jonny Wilkinson-less Falcons.
It was always going to be a tough trip for the Falcons, who secured a seven-point lead after the 10-3 first-leg victory, but with scrum-half James
Grindall scoring an early try and centre Tom May slotting a dropped goal, things were looking good at 13-3 at halftime.
But the powerful Montferrand pack eventually ground the English club into submission, and the home side scored three second-half tries through centre Raphael Chanal, backrower Marc Reynaud and French hero Oliver Magne to sneak
Meanwhile, Castres beat Brive 31-28 at Stade Pierre Antoine, but the visitors go through to the quarter-finals courtesy of their 13-point buffer from the first leg.
Brive earned a match-up with Harlequins next weekend after winger Yves Donguy bagged a brace of tries to keep his side within striking distance of Castres throughout the match.
The boot of Castres' Richard Dourthe proved the difference in the final reckoning, with the former international centre kicking an 80th-minute penalty
goal to split the deadlock after home prop Alessio Galasso had levelled the scores at 28-all with a 76th-minute try.
It was a fiery match, with former Wallaby lock John Welborn and scrum-half Valentin Courrent (both Brive) and Galasso all receiving yellow cards in the