A top-four league finish remains mathematically possible but winning the Europa League represents Arsenal's most realistic way of securing a Champions League return.
With that in mind, Wenger is already planning for the visit of Atleti to the Emirates Stadium, telling a news conference: "I would say this weekend is a preparation for Thursday.
"I rested some players after the [CSKA] Moscow game so they will need a game. [Europe] is the priority because, in the Premier League, we go for not a lot. For us, it's the biggest priority now.
"We are Arsenal and we want to win football games. Every game is important and we love to win. At home, we've had quite a good season, it looks a little bit strange. It's away from home that we failed. It's absolutely important we maintain that record at home.
"We have a big opponent with Atletico Madrid. It's absolutely vital to beat them and have a chance to go to the final and win the competition. Atletico Madrid are seen as the favourite to win the competition but I believe, at our best, we can beat them."
A disappointing result this weekend and a failure to get past Atletico would increase the pressure on Wenger's position, but the 68-year-old says his future is not a concern.
"My personal situation is not so much my worry at the moment," he said. My worry is to transform a season with many disappointments away from home into success. That's what matters to me.
The manager has just been asked for his opinion on safe standing... pic.twitter.com/MH15yUNH56— Arsenal FC (@Arsenal) April 19, 2018
"As I said the other night, my future is in front of me, every time I make a half-turn. It's not my biggest priority.
"If you have to give me some credit, if you look back at my career, you would have to accept that my priority has always been the interest of Arsenal Football Club.
"I'm responsible for the results and when they're not as good as everybody wants, people ask the question. I cannot master that. I can only master my commitment and the quality of my work."
Wenger expects Aaron Ramsey to be fit to face West Ham after a calf injury, although Jack Wilshere and Henrikh Mkhitaryan are expected miss out.