Biarritz (3) 35
Tries: Ngwenya 2, Carizza, Marconnet Cons: Yachvili 3 Pens: Yachvili 3
Ulster (3) 15
Tries: Trimble, Ferris Cons: Pienaar Pens: Pienaar
Iain Balshaw tackles Stephen Ferris during the Heineken Cup Pool Four game
Ulster's Heineken Cup hopes suffered a setback as they were well beaten by Biarritz, who secured a bonus point.
Ruan Pienaar and Dimitri Yachvili exchanged penalties in the first half.
Biarritz scored tries in the second half through Takudzwa Ngwenya (2), Manuel Carizza and Sylvain Marconnet, with Yachvili adding another 12 points.
Andrew Trimble and Stephen Ferris were the Ulster try-scorers, with Pienaar converting Ferris' late touchdown as a consolation for the Irish province.
The French outfit exerted early pressure but Ulster regrouped and while Pienaar missed with a 10th-minute penalty attempt, he made amends with his next effort from an identical position three minutes later.
The visitors came back into the game, squandering several potential try-scoring opportunities, but a 36th-minute Yachvili penalty levelled the scores.
Robbie Diack almost breached the Biarritz defences before the break but he was bundled into touch short of the line by a superb try-scoring tackle from Dane Haylett-Petty.
The hosts came out for the second half with fresh resolve and Magnus Lund provided the pass for Ngwenya to score the first try of the game six minutes after the interval, Yachvili converting.
Two further Yachvili penalties increased his side's advantage and then lock Carizza crossed the Ulster line on 62 minutes, with Yachvili again adding the two points.
Trimble reduced the deficit with his 67th-minute try, which Pienaar failed to convert, but replacement Marconnet completed a fine move for his side's third try three minutes later, Yachvili maintaining his 100 per cent kicking record with the conversion.
The scrum-half also converted wing Ngwenya's second try of the match two minutes before full-time, while Ferris grabbed a late consolation try from a quick-tap, which Pienaar converted.
Ulster's Simon Danielli could be an injury worry for next Friday's Magners League game with Edinburgh as he limped off after 25 minutes of the first half.
David Humphreys, Ulster Director of Rugby:
"The game really showed the difference of experience in Europe between Biarritz and ourselves.
"We should have been 12-15 points clear at half-time but it was a different game in the second half.
"This side must keep improving but we've got good players, some top-class internationals who are proven at the highest level.
"We won't lose heart - we have to keep improving and make sure we're ready for Bath in December."
Biarritz: D Haylett-Petty, T Ngwenya, C Gimenez, M Bond, I Balshaw, J Peyrelongue, D Yachvili, E Coetzee, B August, C Johnstone, J Thion, M Carizza, M Lund, S Vahafolau, I Harinordoquy.
Replacements: R Terrain for August (65), S Marconnet for Johnstone (52), A Barozzi for Harinordoquy (68), B Guyot for Vahafolau (41), D Traille for Bond (52), A Mignardi for Gimenez (76) I Bolakoro for Halylett-Petty (68), Johnstone for Coetzee (69), F Faure for Carizza (65).
Ulster: D McIlwaine, A Trimble, I Whitten, P Wallace, S Danielli, I Humphreys, R Pienaar; T Court, R Best, BJ Botha, J Muller, T Barker, P Wannenburg, S Ferris, R Diack.
Replacements: A Kyriacou for Henry (73), P McAllister for Botha (68), B Young, D Tuohy for Barker (52), C Henry for Diack (62), P Marshall, N Spence for Humphreys (73), A D'Arcy for Danielli (25).