David Moyes has warned Ole Gunnar Solskjaer he will need to improve results soon if he is to remain Manchester United manager.

Scrutiny on Solskjaer has been building in the wake of back-to-back defeats to Arsenal and Istanbul Basaksehir.

United were particularly poor in the Champions League loss in Turkey, with Demba Ba's opening goal – in which he was given a free run from inside his own half following a clearance from a corner – leading club great Paul Scholes to compare the Red Devils' defending to that of an under-10s team.

Solskjaer has overseen impressive victories over Newcastle United, Paris Saint-Germain and RB Leipzig this season, and United had been on a club-record 10-match winning run away from home prior to the visit to Istanbul, but inconsistent performances continue to undermine his position.

They were fortunate to win 3-2 at Brighton and Hove Albion – a match in which the hosts hit the woodwork five times, a record in a Premier League match since at least 2003-04 – and they have lost three and drawn one of their four home league games, marking their worst start to a season at Old Trafford since 1972-73.

Moyes was sacked eight months after replacing Alex Ferguson in 2013, with his final match a 2-0 defeat at Everton, the team United face next at Goodison Park on Saturday.

The West Ham manager knows only too well that pressure on Solskjaer will continue to build if United do not start winning games.

"All managers are under pressure," he said on Friday.

"At Manchester United there is more pressure than any club in the world. It comes with the job.

"We know what happens if you don't win enough games."

Everton are unbeaten in three league games against United, but Carlo Ancelotti's side are on a three-match winless streak, while they have lost 36 Premier League games against the Red Devils, a record in the competition.

Goalkeeper David de Gea, who had a kick blocked into the net by Dominic Calvert-Lewin in last season's 1-1 draw on Merseyside, expects a tough encounter on his birthday.

"To be honest, [a win] would be the best present for me if we beat Everton on my 30th birthday," he told United's website.

"It will be a tough game for sure. They have a good manager and good players and they are playing very well. We need to be ready for the game.

"They are playing very well, like l said. They have signed some very good players and they are scoring a lot of goals.

"It's a very good team and it's always difficult to play against Everton away to be honest, so we need to be very focused, train well and be 100 per cent ready to play against them."