Manchester United slipped to their 14th Premier League defeat of the season -- their joint-most losses in a single campaign since 1989-90 --after being beaten 4-1 at Newcastle United on Sunday.

Despite the absence of ailing manager Eddie Howe, Newcastle boosted their chances of securing a place in next season's Champions League as they sit fourth in the standings with 56 points.

With Howe in hospital due to illness, in-form Newcastle did not lose any of their recent momentum, racing into a 24th-minute lead through a fine Sandro Tonali volley.

The visitors responded well, however, scoring a superb goal of their own on the break, finished off by Argentine forward Alejandro Garnacho in the 37th minute, but Harvey Barnes restored Newcastle's lead early in the second half.

Barnes added a third in the 64th minute, before an error from league debutant Altay Bayindir in the away goal gifted Bruno Guimarães a late fourth to send Newcastle above Manchester City, while Manchester United dropped to 14th.

"We know that it's been a tough season, nothing to add to that," Manchester United captain Bruno Fernandes told Sky Sports. "Our position in the table is not where this club belongs, but unfortunately we are not getting the results.

"We need to look forward as we have a big game coming up, we need to clear our heads and go for it."

Newcastle came into the contest looking to do the league double over Sunday's opponents for the first time since 1930-31.

However, that accomplishment is not the daunting task it used to be. They have been beaten home and away by four teams this season -- the most times that has happened to Manchester United in a single campaign since 1957-58.

Amorim made five changes to his United side for the trip to the north east with Thursday's Europa League quarterfinal second leg against Lyon in mind.

The visitors did quickly find their feet, with Joshua Zirkzee playing a sublime one-two with Fernandes before bringing a fine save out of Nick Pope in the home goal.

The hosts made their first big chance count, however, with Alexander Isak superbly lofting the ball over the visiting backline before Tonali slammed home for the second successive home match.

Manchester United have now conceded first in 19 league matches this term -- their most in a single season since 2013-14, with six games of the current campaign to go.

A superb stop from stand-in visiting goalkeeper Bayindir, making his Premier League debut with first-choice stopper André Onana left at home, denied Isak a quick-fire second.

That save proved crucial as Garnacho finished well on the counter, after good work from Manuel Ugarte to win the ball back. The 20-year-old Garnacho netted his 15th Premier League goal; the second-most by a South American player aged under 21.

The away side needed a solid start to the second half to really get back into the contest, but were too easily broken down by Newcastle full-back Tino Livramento, before Barnes arrived right on cue.

Barnes could not believe his luck as he was allowed the freedom to run straight through the heart of United's backline to become only the second Newcastle player to score a double against Sunday's opponents in the Premier League era.

The calamitous visitors were not done there, as Bayindir's clearance was intercepted by Joelinton, who squared for Guimaraes to seal a fine fifth successive win in all competitions for Howe's team.

"Me and Eddie have worked together for 17 years, and in that time he's never missed more than a day or two, so he must have found it hard to be missing this week," Newcastle assistant manager Jason Tindall told the BBC.

"We went out and delivered a performance he would be proud of. Hopefully he is back very soon."