BILBAO, Spain, April 30 (Reuters) - Winning the Europa League may not save Manchester United's season, but it could still be key to the club's immediate future, both on and off the pitch, manager Ruben Amorim said ahead of Thursday's semi-final clash at Athletic Bilbao.

As United sit 14th in the Premier League with 39 points after suffering 15 losses this season, Amorim believes European success could inject much-needed momentum into a disappointing campaign and into their rebuilding plans.

"Everybody knows (the game against Bilbao) it is really important for our season," Amorim told reporters on Wednesday.

"We know that nothing is going to save our season but this can be huge, winning a trophy and also to get into the Champions League.

"To have those games next year could change a lot of things in our club, even in the summer."

While Amorim sees the Europa League as a potential turning point, he stressed that qualification for the Champions League would not solve all of United's problems.

"It could change our summer, it could change next year," he said. "But we have to deal with a lot of things in our club. We will be fine with Champions League or without Champions League."

Asked about the contrast between United's strong European form and their Premier League struggles, Amorim said he had few answers, but pointed to the team's issues in front of goal.

"I don't know why (we are better in the Europa League). We've had some games where we did not create (scoring) situations, but that's not been the case in the last game," Amorim said referring to Sunday's 1-1 draw at Bournemouth.

"We are creating the chances but we are not scoring goals but sometimes you don't have an explanation. I don't have a big explanation for that.

"We are far from being a really consistent team. We have a clear lack of goals and that has cost us a lot of points this season."

Amidst the debate over whether it is fair for a club with poor domestic performance to qualify for the Champions League via the Europa League, Amorim said United must make the most of the opportunity, regardless of how it is perceived.

"It's the rules. Maybe you could say it's not fair because the best teams should be in the Champions League," he said.

"But I suspect it's done to give value to this competition. If we have that possibility, we should try and reach it."

(Reporting by Janina Nuno Rios in Mexico CityEditing by Toby Davis)

((Janina.Nuno@thomsonreuters.com;))