Ulster are coming off the back of a 9-7 GUINNESS PRO12 defeat to Munster that has seen them drop to sixth in the league table.
Before that, however, they had won three straight matches including a European double over Toulouse and a 10-3 victory over Pat Lam's Connacht.
Despite sitting second in their European Rugby Champions Cup pool, Ulster head into Sunday's match with Oyonnax knowing a win is vital to their chances of making the last eight.
And O'Connor thinks the win over Toulouse in France can provide the platform for Ulster to perform in France.
"It was very very special," he said. "Especially down there putting it up to them. We knew they were going to come out all guns blazing because the French are a different animal at home and it was good just to put them in their box.
"We know what sort of confidence there is in the squad and what we are capable of.
"We know that we are capable of winning big games against big teams and we have to go out all guns blazing and hopefully fire on all cylinders.
"We have to go and get the win and hopefully we can do the job and we'll do our best to get the win.
"We simply have to win, hopefully we can get the performance to go with it."
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