Newcastle scored five tries as they hammered French side Castres to reach the European Challenge Cup semi-finals.
After slipping behind to an early penalty, the Falcons got off the mark through a John Rudd try before Iosefa Tekori restored Castres's lead.
Three Jonny Wilkinson penalties edged Newcastle 14-13 ahead at the break.
And in a one-sided second half, tries from Carl Hayman, Tom Dillon, James Grindal and Brent Wilson sealed Newcastle's first win in six matches.
They will now travel to play fellow Premiership side Worcester in the semi-finals at Sixways on the weekend of 26/27 April.
The only down side for the Falcons was an injury to England centre Jamie Noon, who was forced off after 30 minutes with a recurrence of a shin problem he initially picked up at Leeds a fortnight ago.
Newcastle boss Steve Bates:
"I'm really pleased with the result and the way the boys played.
"We had a really good first half and turning round 14-13 up in those conditions was really excellent.
"We pretty much dominated in most phases of the game. Our defence was outstanding, we scrummaged really well and our lineout functioned well.
"We got the ball forward much more clinically and if we had held on to the ball a bit more the score could have been really something."
Newcastle: Tait, May, Noon, Flood, Rudd, Wilkinson, Grindal, Ward, Thompson, Hayman, Perry, Sorenson, Buist, Woods, Dowson (capt)
Replacements: Long, Golding, Wilson, Winter, Charlton, Dillon, Visser
Castres: Teulet, Milford, Mazars, Marticorena, Bourret, McIntyre, Meeuws, Bonello, Ducalcon, Capo-Ortega, Tekori, Vosloo, Tabacco, Senio
Replacements: Terrain, Saayman, Adamou, Tomiki, Jaca, Benassis, Lagardere
Referee: Peter Allan (Sco)
Newcastle (14) 40
Tries: Rudd, Hayman, Dillon, Grindal, B. Wilson Pens: Wilkinson (2) Cons: Wilkinson (3) Drops: Wilkinson
Castres (13) 13
Tries: Tekori Pens: Teulet (2) Cons: Teulet