MANCHESTER -- Manchester United manager Jose Mourinho has admitted Romelu Lukaku is unlikely to get a rest until Zlatan Ibrahimovic returns from injury.
Lukaku has made a flying start to his Old Trafford career with 10 goals in his first nine games, including two against CSKA Moscow on Wednesday. The Champions League clash in Russia was his 11th game of the season after also appearing in two World Cup qualifiers for Belgium last month.
Lukaku hasn't missed a minute in the Premier League or the Champions League. And Mourinho concedes the 24-year-old's workload will not get lighter until Ibrahimovic returns, which the United boss has suggested may not be until the new year.
"Without Zlatan we cannot rotate the striker, especially because Marcus Rashford is playing also in other positions," Mourinho said ahead of Crystal Palace's visit to Old Trafford on Saturday.
"So until the moment we have Zlatan we cannot think about giving rest to our No. 9, the same way we give in other positions. We cannot do that."
Lukaku has been named in the Belgium squad for qualifiers against Bosnia and Cyprus during the international break, along with midfielder Marouane Fellaini, who is nursing an ankle injury.
Roberto Martinez's team have already qualified for next summer's tournament in Russia. But Mourinho insists he will not put pressure on the former Wigan and Everton manager to give Lukaku a break.
He added: "Belgium is Roberto's responsibility and it's his decision to play him or not to play him. It's Roberto's responsibility. I cannot, professionally speaking, say do this or do that, you know. It's Roberto's responsibility."
Lukaku arrived from Everton in the summer tasked with filling the void left by Ibrahimovic, who has not played since April after undergoing knee surgery. He is also shouldering the goalscoring responsibility in a team that could only manage 54 goals in the Premier League last season.
United have already scored 29 in all competitions this campaign -- a mark they didn't reach until Nov. 19 last season -- and Mourinho says Lukaku is already handling the pressure of being United's main goalscorer.
He said: I don't want to speak about his progress. If I do that, it looks like we did something extraordinary in three months that he didn't have in the remaining years of his career.
"I don't think it's fair. It's just a global evolution. I think every step in his career he got it, he grabbed it with both hands.
"Since his first loan to West Bromwich Albion, grabbed the opportunity with both hands, fighting for his evolution. He was very strong in his desire to be playing in a team with other objectives now, with Champions League football, was always his dream to come to this level and since he arrived I don't think he thinks in another thing than in his success.
"So he works hard, he rests, he has a great professional life outside the football pitch. He has ambitions, he enjoys.
"So I think he's a global evolution. I wouldn't be fair, I wouldn't say that every step in his career with different managers, with different fellow players, with different teams, is not contributing to what he is now.
"And now of course I think Manchester United is a different level of expectation and he's coping well."