Clermont Auvergne 27 (6)
Biarritz Olympic 17 (17)
Stade Marcel Michelin

Defending champions Clermont Auvergne rallied from 17-3 down to beat Biarritz 27-17 on Friday night, and book their place for a semi-final showdown with Stade Toulousain.

Clermont were stunned by two first-half tries from Biarritz as they initially fumbled their lines, but they fought back to score 21 unanswered points in the second period, with Brock James, Alexandre Lapandry and Julien Malzieu all touching down - although two of those tries came in controversial circumstances.

Scrum-half Morgan Parra converted two of the three tries, with James kicking the other to complete the turnaround and set up a mouth-watering semi-final against Toulouse in Marseille on May 27. If they can win that they will then go on to contest an incredible fifth successive Top 14 final.

Clermont started positively enough with full-back Anthony Floch landing a long-range penalty on 14 minutes to open the scoring, but the champions were subsequently hamstrung by unforced handling errors as they failed to build on their early lead.

Biarritz scrum-half Dimitri Yachvili levelled the scores with a 20th-minute penalty for the visitors, and the Basques then stunned their hosts with two opportunistic tries in eight minutes as they surged into an improbable 17-3 lead.

First over was Yachvili as the French international jumped on Clermont indecision and then beat off two tackles to touch down on the half hour. He duly converted his own conversion to make it 10-3, but the Basques weren't finished there.

Eight minutes later fly-half Julien Peyrelongue charged down a James kick as Clermont pushed for a response, with the Biarritz No 10 going on to run in from 80m as the Stade Marcel Michelin looked on in stunned disbelief.

Yachvili was again on target to add the extras, with Clermont chipping three points back just before the break when Parra knocked over a 40th-minute penalty.

The half-time score may have been harsh in terms of possession, but Biarritz could not be faulted for taking their opportunities and maintaining a ferocious defence.

When Parra missed a 47th-minute penalty it seemed it just might not be Clermont's evening, but their mounting pressure eventually told when Biarritz full-back Iain Balshaw was yellow-carded for a professional foul on 56 minutes.

One minute later and James initiated the Clermont fight-back when he scooted over after a quickly taken penalty, though Biarritz were furious as they were still contesting the ref's decision. The try gave 'Les Jaunards' renewed impetus and a second score followed when flanker Lapandry jumped on a Marcelo Bosch mistake to claim try number two. The initial break had been made by Fijian youngster Kini Murimurivalu, with the replacement winger kicking ahead for Lapandry to poach his score after Bosch's seeming touch down behind his own try-line was deemed insufficient after a lengthy review by the television official. It was a crucial decision, and one that gave Clermont the lead after the TMO ruled that Bosch had not been in control of the ball when he slammed it down.

Parra's conversion made it 20-17 and the result was sealed when Clermont's Julian Malzieu grabbed their third score with just five minutes left after Gonzalo Canale had created the opportunity. Parra's conversion took the hosts 10 points clear, leaving Biarritz to ponder another night of what might have been as their season came to a disappointing end.

Biarritz coach Laurent Rodriguez praised the effort of his players and said that Lapandry's try had been the game-breaker. "I want to see cold images of what happened on this try, and perhaps a little more analysis. When it takes so long to decide there is concern," he said.

Clermont scrum-half Parra paid tribute to the immense backing his team had received from their home fans. "I thank the public who supported us throughout, who always believed in us even when we were 17-3 down. It gave us the strength not to let go. We saw tonight that this squad has character. Now we must remain humble and keep improving," he said.

The France international went on to add that Clermont would "need something beautiful" to beat Stade Toulousain in Marseille, but backed his team to succeed.

Clermont Auvergne starting XV: Floch, Fofana, Joubert, Canale, Malzieu, James, Parra, Lapandry, Lauaki, Bonnaire, Privat (capt), Cudmore, Scelzo, Ledesma, Debaty. Subs: Ti Paulo, Faure, Pierre, Vermeulen, Senio, Russell, Murimurivalu, Zirakashvili

Biarritz starting XV: Balshaw, Ngwenya, Bosch, Mignardi, Bolakoro, Peyrelongue, Yachvili, Harinordoquy (capt), Lakafia, Lund M, Taele-Pavihi, Lund E, Johnstone, Terrain, Coetzee. Subs: Guinazu, Afoa, Thion, Lauret, Lesgourgues, Tranier, Haylett-Petty, Marconnet (23rd man)

Semi-finals: (to be played at Stade Vélodrome, Marseille)

Stade Toulousain v Clermont Auvergne
Racing-Métro 92 v winner of Castres/Montpellier