The first half was a poor advertisement for rugby union, with neither side showing the flair and talent required to score a try. Warwick banged over a penalty goal on either side of his yellow card for a late tackle, but he was cancelled out by two goals from opposite number Regis Lespinas.
Robinson dotted down early in the second half, and Connacht defended well against the home side, who scored their only try through lock Samuel Nouchi. Connacht have reached at least the quarter-finals of the tournament for the past three seasons and will aim to continue that reacord in the new look tournament.
In the other European Challenge Cup match Narbonne registered a 20-14 score over Italian club Viadana.
The Frenchmen were leading by that score as the second half started, but Irish referee David Keane was forced to call the match off because of fog. A decision on whether the score and result will stand or whether the game will be replayed will be made by the ERC Board.