The Spanish tactician has warned Sevilla to be at their best in order to stand a chance of qualifying to the competition’s final at the expense of Ole Gunnar Solskjaer’s men.
Sevilla have been undefeated in 19 games since their defeat against Celta Vigo in early February and their quest for another success in the Europa league have been boosted with wins against AS Roma and Wolverhampton Wanderers in their last two games.
Despite a scrappy win against Copenhagen in the last quarter-final game, the Red Devils have lost one in their last 24 games in all competitions.
Sevilla stunned Manchester United at Old Trafford in the Champions League Round of 16 game two years ago but Lopetegui has insisted that Sunday’s game in Cologne will be different as he is certain the English side are better.
“This United is the best Manchester United in recent years, a team that has found its way, that's why they haven't lost in the Premier League since January," the former Real Madrid boss told reporters ahead of the game.
"They have found the space for the many quality footballers that they have. They are complete, they will force us to play a great game to compete with them.
"This is what I hope for tomorrow, a semi-final in a game of maximum difficulty and that will require us at all levels to play collectively.
"We like to play beautiful and important matches. For that we have fought and worked all year. It is an important game against a great opponent.”
“We will be able to arrive prepared. We will try to overcome them, no matter how big a team they are."