The Gunners are currently third, with Tottenham and Newcastle just one and two points behind them respectively, and both wll be looking to pounce on any lapse at the Hawthorns.
Wenger told reporters: "Before this game, we are in a fantastic position and, if we win, we don't need to look at anything else. We want to finish third.
"For long periods this season our fate has not been in our own hands, but it is now. We have to look at this final match as an opportunity, and one we have to take."I feel we are focused, switched on and I'm confident we'll do well. For us it is just to find the right mixture – to be focused, combative and relaxed, and especially be faithful to play our football like we want to.
"We have known final days like this before, games where we've been playing for titles, or to qualify for the Champions League. We are used to coping with that.
"If we have more of the ball than West Brom, like we want to have, we will have more chances to win the game. That is what we will focus on. Just be faithful to the way we want to play football."
North London rivals Tottenham were 13 points clear of Arsenal in third back in February, and winning 2-0 in the derby before Arsenal turned that match, and the league, on its head by winning 5-2.
He added: "Three months ago, everybody would have been happy to be going into the final game with this situation. The Premier League is difficult. We came from a deep position in the league but, if you look at the way we've made to be where we are today, it's remarkable."
Arsenal pipped Tottenham to a Champions league spot in 2006 amid controversy surrounding several Spurs players falling ill on the morning of their final game of the season, and while Wenger cheekily denied involvement then, he confirmed he would be taking measures to prevent his side suffering similarly.
He smiled: "I didn't cook that day. If I had, more of them would have been ill. But we will certainly be eating here, at the training ground, on Saturday night."