It was the last thing Manchester United manager Ruben Amorim needed.

After taking goalkeeper Andre Onana out of the firing line for Sunday's trip to Newcastle, the Portuguese watched forlorn as replacement Altay Bayindir conceded four goals in a chastening defeat at St James' Park.

To makes matters worse, the Turkey international was to blame for Newcastle's fourth after a poor pass.

"We did a lot of mistakes that made it harder to win a game - that's all," said Amorim. "It's a little bit of everything, it's hard to point to one thing."

With a crucial Europa League quarter-final second leg to follow against Lyon on Thursday, United are keen to put defeat in the north-east quickly behind them.

But Amorim now faces a potentially season-defining decision of whether to recall Onana or stick with Bayindir.

Whether Onana was rested or simply dropped for the visit to Newcastle, the fact he wasn't even named on the bench was a brave decision from the United boss.

Speaking before kick-off, former Manchester United captain Roy Keane said Amorim's patience with the Cameroon international had worn out.

"I think he (Onana) has done OK in the Premier League because United defensively actually haven't been too bad," Keane told Sky Sports.

"The keeper has made some big mistakes and he's been punished for it, so it's a big call for the manager."

Onana came under fire again following two costly errors in the 2-2 first-leg draw in Lyon last Thursday.

Since the start of last season, the 29-year-old has made eight errors leading to goals in all competitions, the most of any keeper playing for a Premier League club.

"The situation has been coming," former England goalkeeper Paul Robinson told 5 Live.

"A lot of Manchester United fans have been getting frustrated with him and there is a time where you do need to take the goalkeeper out of the firing line because the pressure does become too much.

"When you're in front of the opposition fans, you're reminded of your poor form every time you touch the ball and sometimes you do need a rest.

"It's good man-management to put your arm round him and say, 'look you're still my number one goalkeeper, but at the moment you're not playing to the levels I want you to play at - I'm going to take you out, whether it's one, two or three games'."

Amorim may have been keen to stress Onana's omission was a one-game decision, but you don't drop your first-choice keeper at this stage of the season and do so lightly.

Bayindir, a £4.3m signing from Fenerbahce in 2023, has waited patiently for his first start in the Premier League.

But the 26-year-old failed to grasp his opportunity against Newcastle, conceding four of Newcastle's six shots on target and flapping at a number of crosses.

He attempted 57 passes, but completed just 27 of those - an unimpressive rate of 47.4%.

The most costly of those passes came 13 minutes from time, when Bayindir attempted a chipped pass into midfield that was cut out by Joelinton, allowing Bruno Guimaraes to add a fourth goal.

Newcastle were already on their way to victory by then, but the passage of play underlined why, even with Onana making so many errors, Amorim has tended to keep faith with the former Inter Milan stopper.

Amorim, understandably, was keen to move on from the defeat by Newcastle and stressed several times in his post-match interview how the focus was now firmly on the visit of Lyon.

It's the biggest match of his United reign so far, keeping hopes alive of a trophy and place in next season's Champions League, but the Portuguese was giving nothing away when asked if he would recall Onana.

"You have to wait, we are going to start the next week," said Amorim. "I'm going to choose the best starting XI for the next match."

Robinson, though, thinks Onana's spell on the sidelines will continue.

"I don't think he's going to play [against Lyon]," said the former Tottenham goalkeeper.

"You don't take him out for just one game, put him in a few days later and expect him to be on top of his game. I don't expect to see him play on Thursday."