United are currently fifth in the table, just one point off neighbours Manchester City, with both teams vying for a place in the top-four to secure the final qualifying berth.
It has been another largely unsuccessful season at Old Trafford under Dutch manager Louis van Gaal, with United crashing out of the Champions League in the group stage before being eliminated by fierce rivals Liverpool in the Europa League round of 16.
The perennial title challengers have been off the pace domestically this year, with the unpredictable campaign seeing surprise package Leicester City top the Premier League standings with six league matches remaining.
Fellaini himself has also struggled this term. The Belgium international has come under fire for below-par performances and is seen by many fans to symbolise the current failures at the club.
United take on title-challengers Tottenham at White Hart Lane on Sunday, knowing that a positive result will be crucial to maintain their fight to claim a place in next season’s elite European tournament.
“It’s a big, big game,” Fellaini is quoted as saying by the Manchester Evening News.
“Tottenham are near the top of the table. But it’s a huge game for us as well.
“We want to be in that top four. A club like Man United has to play Champions League so we will go there and do our best to try and win the game."
The 28-year-old added: “The quality we have we can beat anyone, and I think we’ve shown that.
“But we have to be there in the right moment. We will do our best on Sunday and hopefully we can get there.”