Jose Mourinho will be a success at Manchester United, according to Fenerbahce boss Dick Advocaat, but the Dutchman has warned the Portuguese is "not a magician".
Mourinho has faced criticism after collecting fewer points from his first 10 Premier League games in charge than David Moyes managed in his spell at the club, after United were held 0-0 by Burnley on Saturday.
United have only scored one goal in their last four league games but former Sunderland manager Advocaat, speaking ahead of Thursday's Europa League clash in Turkey, offered support to Mourinho.
"This man has proved himself in all countries," Advocaat said. "If you see how many prizes he has won it's almost unbelievable - but he's not a magician.
"Quality wise, when you have such players as United it's still difficult to find [the best team]. Is it [Anthony] Martial, [Marcus] Rashford, [Wayne] Rooney? It's quite difficult.
"I'm quite sure they will play for the first place, no doubt about that, and they will start winning games as well. [Zlatan] Ibrahimovic will start scoring goals as well, because that man knows how to score.
"At the moment not everything is going the right way. You see the amount of chances last Saturday, it's unbelievable they didn't score. If you don't create chances that's a different story. There's no reason to be worried about the team and the manager."
Advocaat insists Fenerbahce will not play for a draw against United, despite suffering a 4-1 loss to Mourinho's men at Old Trafford two weeks ago.
"First of all we always go out to win the game," he said. "Playing with that organisation we can stop United, but if we have the opportunity to attack we will. But we play against Manchester United, a great team with great players.
"A home game is different. With the fans behind us we have seen against Feyenoord that it can help. We always have the adventure to win the game and not to go out to pay for 0-0. But we play against another team."
Robin van Persie scored a consolation goal for Fenerbahce on his return to Old Trafford, but the veteran Dutchman is an injury doubt for Thursday's game.