The result means Worcester now only have a one-point lead going into the second part of the Bourgoin double-header at Sixways Stadium on Saturday (December 13).
Director of Rugby Ruddock admits harsh words were said at the Stade Pierre Rajon in defeat and has now demanded his team bury the memory of defeat when the two sides lock horns again next weekend.
"I was very disappointed with the manner of our display and our performance," admitted Ruddock. "I was looking for a backlash after last week's defeat against Saracens and we didn't get it which was extremely frustrating.
"We conceded almost straight from the kick-off which was a result of a turnover by us, we conceded from our own possession and our mistakes which is not good enough. We gave them a dream start before we knew it.
"We got back into the game with a try from Alex Grove which was well worked by us. But just before half-time another moment of poor play resulted in another turnover which Bourgoin picked up and scored from.
"Instead of being 13-7 down at the break - a position from which I always felt the game was very winnable for us - we were down 20-7.
"There were some harsh words at the break and we were much better in the second half as we stopped them scoring and created a great try of our own. But even so we conceded penalties."
Worcester and Bourgoin produced an explosive first encounter and the sparks are set to fly when the two sides meet again next weekend.
And Ruddock has already outlined to his players what he expects on home soil.
"We have always set high standards in this competition from day one. I now want to see a large win next week and a big reaction. I want the players to bury the display in France," he said.
"I was really disappointed with the two tries we conceded. We had to work to score two excellent tries but then we gifted them two tries from two turnovers. I have told the players that it is unacceptable and cannot be repeated again."