Paris - South African duo Demetri Catrakilis and Bismarck du Plessis inspired Montpellier to a 22-12 win over Newport on Saturday to set up a Challenge Cup final date with Harlequins.
Flyhalf Catrakilis kicked 17 points with hooker Du Plessis powering over for a 60th-minute try at the high-flying French Top 14 club's Altrad Stadium.
Welsh visitors Newport, who had despatched champions Gloucester in the quarter-finals, outscored Montpellier with two tries in a late second-half fightback from Hallam Amos and Carl Meyer.
But it was insufficient as Montpellier, coached by South African World Cup winner Jake White, largely dominated the first half.
They held a 15-point lead on the hour when Australian scrumhalf Nic White produced a pinpoint kick to earn a five metre line-out.
Du Plessis found fellow Springbok Pierre Spies at the end of the line, and then joined in to claim the try.
With Catrakilis converting the hosts were 22 points clear, but Newport went down fighting with Meyer setting up Amos before the fullback crossed himself two minutes from time.
Montpellier's reward for their tenth consecutive win in all competitions was a first ever European final.
On Friday English side Harlequins, seeking their fourth title, progressed to the May 13 final in Lyon with a 30-6 home defeat of Grenoble.
"At Montpellier, we don't play in a lot of finals," said the victorious French side's captain, Fulgence Ouedraogo. "That's why this is so important.
"That's what we're missing, winning titles. We want to start with this final in Lyon.
"We're expecting a tight final against a Harlequins side that is very strong."