Biarritz kept alive their faint hopes of qualification for Heineken Cup quarter-finals as they beat Connacht at a sodden Parc des Sports Aguilera.
The French club dominated possession and Connacht never threatened the Biarritz line in the contest.
After Dimitri Yachvili's early penalty, Connacht somehow held out until Iain Balshaw's 31st-minute try.
Connacht defended gamely in the rain-lashed conditions before Seremaia Burotu's late try for the home side.
By the end of the game, the players looked as if they had been taking part in a bog snorkelling contest, such were their muddied appearances.
Heavy rain in the south west of France had put the contest in doubt and the game started with pools of water already on the pitch.
Biarritz's shock defeat in Galway last week had led club president Serge Blanco to dispense with their services of coach Jake Isaac and his assistant Serge Milhas.
The club's athletic director, former France forward Laurent Rodriguez, took charge for Friday's game after being handed temporary control by his former international team-mate.
Johnny O'Connor's inclusion was Connacht's only change from last weekend's win and he was guilty of conceding a third-minute penalty as he illegally dispossessed fit-again Imanol Harinordoquy, which allowed Yachvili to score from in front of the posts.
As Biarritz continued to press, winger Takudzwa Ngwenya appeared to have scored in the 12th minute but the video correctly showed that he had not grounded before skidding off the saturated pitch.
Connacht were being forced to soak up constant pressure and Parks' positioning in the number 13 channel meant that he was struggling to get any distance with his clearance kicks.
Biarritz's pressure finally yielded a try for the impressive Balshaw in the 31st minute after quick hands from Jean Pascal Barraque and Damien Traille as the Top 14 club had numbers out wide, with Parks caught out in defence.
Yachvili added the conversion but missed a further penalty chance before the break as Connacht were probably relieved to only be 10-0 in arrears.
After Benoit August was yellow carded for some illegal handling on the floor on 47 minutes, Parks had a chance to open Connacht's account from 40 metres but in the dreadful kicking conditions the former Scotland international was off target.
An injury to Connacht's South African centre Danie Poolman led to a long delay as he had to be stretchered off the field after taking an accidental knee to the head in a ruck.
As some Biarritz frustration started to set in, replacement Thibault Dubarry was sin-binned by referee Leighton Hodges after tangling with Leinster-bound Mike McCarthy.
But once again Connacht were unable to profit from the man advantage and Biarritz replacement Burotu scored in the final minute after Traille's chip and chase, with man of the match Yachvili slotting a superb conversion.
Biarritz: Iain Balshaw; Takudzwa Ngwenya, Jean Pascal Barraque, Damien Traille, Aled Brew; Julien Peyrelongue, Dimitri Yachvili; Fabien Barcella, Benoit August, Francisco Gomez Kodela; Erik Lund, Pelu Taele; Wenceslas Lauret, Raphael Lakafia, Imanol Harinordoquy (c).
Replacements: Seremaia Burotu (for Barraque 77), Wicus Blaauw (for Barcella 73), Jean-Philippe Genevois (for August 67), Thomas Synagehel (for Gomez Kodela 61), Magnus Lund (for Lauret 74), Thibault Dubarry (or Harinordoquy 57).
Not Used: Lesgourgues, Bosch
Connacht: Robbie Henshaw; Tiernan O'Halloran, Danie Poolman, Dave McSharry, Fetu'u Vainikolo; Dan Parks (capt), Kieran Marmion; Brett Wilkinson, Jason Harris-Wright, Ronan Loughney; Mick Kearney, Mike McCarthy; Andrew Browne, Johnny O'Connor, Eoin McKeon.
Replacements: Matthew Jarvis (for Poolman 57), Miah Nikora (for Parks 69), Paul O'Donohoe (for Marmion 57), Ethienne Reynecke (for Harris-Wright 67), Nathan White (for Loughney 49), George Naoupu (for Kearney 49), Danny Qualter (for Browne 77).
Not Used: Denis Buckley.
Referee: Leighton Hodges (Wales)