Jose Mourinho has heaped huge responsibility on the shoulders of Romelu Lukaku

Lukaku has scored 10 goals in nine matches for his club and four in two appearances for his country.

Mourinho said it would be Roberto Martinez's decision whether to rest Lukaku for Belgium's impending World Cup qualifying matches against Bosnia-Herzegovina and Cyprus given that they have already qualified for Russia.

But the Portuguese was adamant that Lukaku would continue to start for United - at least until the return of Ibrahimovic gives him another option.

Mourinho, who confirmed that Paul Pogba's torn hamstring was a "long-term" injury, said previously that he expects to have the Swede available from January although the player is targeting December.

"Look, without Zlatan, we cannot rotate the striker, especially because Marcus Rashford is playing also in other positions," Mourinho said ahead of today's visit of Crystal Palace.

"So until the moment we have Zlatan we cannot think about giving rest to our number nine, the same way we give in other positions. We cannot do that.

"I think every step in his (Lukaku's) career, he grabbed it with both hands.

"It was always his dream to come to this level and since he arrived I don't think he thinks about another thing than in his success so he works hard, he rests, he has a great professional life outside the football pitch."

Mourinho scoffed at suggestions United's strong start to the season is down to a favourable early fixture list.

"Your colleague was basically saying that we have good results because we are playing against bad teams," he said.

"I don't think Everton, West Ham, Leicester will be happy with that, but we have our feet on the ground. We are humble, we know that the great teams of the Premier League we didn't play them yet so we are calm."

Meanwhile, Mourinho has been summoned to appear in a Madrid court on November 3, two days before United face Chelsea, over alleged tax evasions claims. (© Daily Telegraph, London)