MANCHESTER, England, Dec 1 (Reuters) - Days after new Manchester United ( MANU ) manager Ruben Amorim said striker Marcus Rashford has to "want it" if he is to rediscover his best form, the 27-year-old scored twice in United's 4-0 rout of Everton on Sunday.

Amorim, however, warned that Rashford, who has scored three times since the Portuguese took charge barely a week ago, cannot rest on his laurels after his first double in a league game for almost two years.

"He can do so much, so he has to continue to improve, he has the ability to do it, he already proved that," Amorim said of Rashford, who poured in 30 goals across all competitions in a standout 2022-23 season.

"But he can play so much better, as can the other guys. Was a good performance, (but) tomorrow he has to recover and start thinking about Arsenal."

Rashford sounded keen to live up to the challenge.

"(Amorim) is definitely demanding but gives encouragement to bring your strengths into the game. That is when you get a really good team performance," he said. "Hopefully, we can build on this and keep pushing. We have to keep pushing every day to meet his demands."

Joshua Zirkzee also bagged two goals as United's rout of Everton lifted them three places to ninth in the Premier League table, but Amorim, whose team travel to second-placed Arsenal on Wednesday, said it was too soon for fans to think about a return to the Champions League.

"It's hard for me, if I say no (United won't return to Europe's elite competition), you will say that I cannot be a Manchester United ( MANU ) coach, but I want to be honest with our fans," Amorim said.

"So, let's focus on the performance, not the results. In the end, I said this many times, I will be judged about the place that we finish. I know that. But let's focus just on the next game and look at the performance."

Amorim had kind words for 22-year-old forward Amad Diallo, whose relentless pressure unsettled Everton all afternoon and created two of United's goals.

"It was really good again, he's in a great moment, but that moment started with Ruud," Amorim said, paying credit to Ruud van Nistelrooy, who was interim manager for four games after Erik ten Hag's sacking.

"So I just take advantage of Ruud's work with Amad. He was really good defending and really good attacking. So he has to continue to play like that. You could feel it in the end of the game, he was really, really tired."