Worcester remain winless
Jeremy Su'a scored after 19 seconds but Worcester eventually lost 33-25 to Biarritz in their Amlin Challenge Cup clash on Thursday.
Su'a scored after 19 seconds and Biarritz had a prop sent off but that still was not enough for the Warriors to claim their first win in the Amlin Challenge Cup this season.
Dean Ryan's team led for all but eight minutes of a thrilling European clash at Stade des Sports Aguilera yet still finished without a point.
Instead two tries each by Teddy Thomas and Yann Lesgourges saw the Basque club come from behind to win for the second time in a week while Benoit Baby's last-minute penalty denied Warriors a losing bonus-point.
It had looked a different story when scrum-half Su'a charged down a kick to score inside the opening minute.
Max Stelling and Paul Warwick followed in the second half, either side of a second yellow for Biarritz prop Thomas Synaeghel, while Ignacio Mieres also kicked 10 points.
But 14-man Biarritz stormed back with a late flurry to overtake Sale Sharks at the top of Pool 1.