MANCHESTER, England: In his own words, Andre Onana arrived at Manchester United last year as the “best goalkeeper in the world.”

Within weeks his reputation had taken a battering and he was left needing to protect his mental health.

“It was for me in certain moments like ‘What happened?’” Onana said as he prepared for Saturday’s FA Cup final against Premier League champion Manchester City at Wembley Stadium.

A serial title winner with Ajax and a Cameroon international, Onana moved to United from Inter Milan for $57 million in the offseason. As a modern ball-playing keeper, he was seen as pivotal to manager Erik ten Hag’s plans to mount a Premier League and Champions League challenge.

But a series of costly errors in his opening weeks at the club saw him become a figure of ridicule on social media and a symbol of United’s troubled campaign.

“When I arrived here, I arrived as the best goalkeeper in the world and ‘boom’ it went down and you see how difficult football is sometimes,” Onana said. “I decided to not stay there, but to stand up and fight to the end. I know who I am. I know what I did to arrive here and never forget what you did.

“Never stay too high, but also don’t stay too low because at the end of the day, being a player for such a big club, when you win it’s top and when you don’t win it’s terrible. You have to stay in between and feel your mind and have your mental health safe because it is not easy to play for such a big club.”

The 28-year-old Onana said it took him six months to “feel good” at United. For all his difficulties, he was brave enough to accept culpability and give interviews after an error-strewn performance in a loss to Bayern Munich in the Champions League in September. But the blunders kept on coming.

Eventually Onana’s form improved. United’s didn’t.

Saturday represents the last chance to salvage a season that has seen the 20-time league champion suffer its lowest finish in the Premier League era — eighth. There were 14 league defeats — the most in 34 years.