They say that recent Manchester United managers have left the club looking a decade older than when they arrived, and after just 56 days in the hot seat, Ruben Amorim is already cracking jokes about how it is changing his appearance.

The 39-year-old was the club's youngest appointment since Wilf McGuiness followed Sir Matt Busby in 1969, but after his first couple of months in the job saw United lose six of their 11 games and plunge head-first into a relegation battle, Amorim is seeing the ageing process take hold.

His counterpart across the city, Pep Guardiola, recently suggested that he was struggling to sleep and couldn't digest food, so concerned was he with stopping the rot at Manchester City. Guardiola and Amorim could certainly compare notes on a sleepless night or two, given the travails of their teams at the Etihad and Old Trafford in the last two months.

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Guardiola's comments were put to Amorim ahead of a trip to Liverpool that might have had him waking up with cold sweats, and asked how he switched off from the pressure of losing, he suggested he couldn't.

"You can see in my face," he joked, pointing to his features." You can compare the way I arrive and now!

"Of course when you are losing there is a lot of pressure, for me it’s more the pride and also the performance. I think it’s harder when we don’t perform well."

Amorim was expecting a run like this, which has seen United lose five of their last six Premier League games and all their last four in all competitions. He pointed out as much after his third game in charge ended with a 4-0 win against Everton and questions on whether he could get the club back in the top four. Now, the questions are about relegation.

Rather than switching off, Amorim's help comes from training sessions with the players and the chance to help them improve. But over Christmas, he also got a welcome bonus, with his wife, Maria, and their two children joining him in Manchester on December 27.

Amorim left The Lowry Hotel just before Christmas and moved into a temporary home in South Manchester with his family, a change in living arrangements that he believes will benefit him.

"I have my family now here so it’s so much different, it can help me. They came on the 27th. It was a good day," Amorim said with a smile wider than we've seen for a while.

That smile will come under pressure at Liverpool on Sunday as Amorim takes his team to the league leaders with confidence already in short supply. He has been honest about the threat of relegation and insists there can't be any complacency about his side's peril.

“I know it is a problem here for the manager to say those kinds of things but, in this moment, in our club, everybody has to understand that," he said.

“So let’s focus on the reality. We know that we are Manchester United. I know I am not supposed to talk about these things. But I want to be very clear with the fans and the players. I think that is really important in this moment.

“Anything can happen, but we must be focused on winning games and improving our performance. Then it (relegation) won’t be an issue in the future.”