Williams wants Munster reaction in France
Les Kiss's side were edged out 9-7 at the Kingspan Stadium last weekend to end a four-match winning streak.
However, they have the chance to find that winning feeling again as they continue their Champions Cup Pool One campaign.
The Belfast side are back in the race for the quarterfinals after back-to-back triumphs over Europe's most successful side, Toulouse.
The unbeaten Saracens are streaking away with the pool after four successive European wins, but Ulster are hoping to claim a best runners-up spot.
Their chances will be boosted if they can overcome Oyonnax at Stade Charles Mathon, with the hosts yet to win a match in their maiden Champions Cup campaign.
And Williams reckons the Ulstermen will learn their lessons from the Munster defeat.
"Look, we've got to have an honesty session this week, putting things to bed first and then we'll think about France," Williams said.
"There'll be a few questions asked after the result against Munster, but we'll learn from that and from the video sessions we'll all have.
"But this squad is a quality group of players, and one poor performance, one bad result, doesn't put us off-track.
"Immediately after a game like this against Munster you are a bit 'down', but overall there's a lot to be positive about and when we get this out of our system, been honest with ourselves, we'll be ready and confident for Europe.
"I'm unhappy that after that Munster game we haven't maintained the momentum and the standards we have set ourselves, but I have absolutely no doubt we'll look back on the weekend as an unfortunate 'blip', and we can really kick on now."
Source: @ChampionsCup
