Harlequins kicked off their Heineken Cup campaign with an impressive 40-13 victory over Biarritz at The Stoop in Twickenham.
England scrum-half Danny Care scored the opening try before Arnaud Heguy helped the French draw level to 13-13 at the interval.
But Quins ran riot in the second half with tries from Rob Buchanan, Jordan Turner-Hall and Seb Steggman.
"The players were so positive at half-time and that was good. We kept on trying to play and we knew the scores would come," said Quins director of rugby Conor O'Shea.
Final Score Harlequins 33 (13) Biarritz 13 (13)
Tries: Care, Buchanan, Turner-Hall, Stegman
Penalties: Botica 4
Conversions: Evans, Botica 3
Penalties: Peyrelongue 2
Harlequins: Mike Brown, Tom Williams, Matt Hopper, Jordan Turner-Hall, Ugo Monye, Nick Evans, Daniel Care, Joe Marler, Rob Buchanan, James Johnston, Ollie Kohn, George Robson, Maurie Fa'asavalu, Chris Robshaw (capt), Nick Easter
Replacements: David Ward, Mark Lambert, Will Collier, Charlie Matthews, Tom Guest, Karl Dickson, Ben Botica, Seb Stegmann
Biarritz: Iain Balshaw, Takudzwa Ngwenya, Dane Haylett-Petty, Seremaia Burotu, Aled Brew; Mathew Berquist, Yann Lesgourgues; Fabien Barcella, Arnaud Heguy, Francisco Gomez Kodela, Erik Lund, Thibault Dubarry, Magnus Lund (capt), Wenceslas Lauret, Talalelei Gray.
Replacements: Benoit August, Wicus Blaauw, Thomas Synaeghel, Pelu Taele, Benoit Guyot, Julien Peyrelongue, Damien Traille, Benoit Baby