The Turkish goalkeeper, unexpectedly chosen over Andre Onana, misjudged a Declan Rice corner, allowing Riccardo Calafiori to head home unchallenged and secure Arsenal's victory.

The error drew sharp criticism, with former United captain Roy Keane suggesting Bayindir needed to show more "violence" to dominate his penalty area during set pieces. Amorim, however, backed his goalkeeper, urging United to match their opponents' physicality. "You can do a lot in the box on corners, and we must do the same," he said.

"Bayindir chose to go for the ball, not push players. That's allowed by the rules, but he didn't push, so he couldn't defend it. We need to adapt."

When pressed on Bayindir's error, Amorim was quick to highlight his goalkeeper's past heroics. "When did he last concede like this?" he challenged reporters.

Reminded of a similar incident against Tottenham last season, Amorim countered, "That was without VAR, it would've been a foul. And in the next Arsenal game, who saved a penalty? Who saved the match? Altay was outstanding. I pick my goalkeeper based on everything I see, and I chose Altay."

Amorim also clarified his decision to omit Onana, United's regular number one last season, from the squad. "It wasn't about dropping Onana," he explained. "He's only had three training sessions since a hamstring injury and isn't ready. Tom Heaton and Altay Bayindir performed well in pre-season, so I went with them."

Despite recent links to goalkeepers like Gianluigi Donnarumma, who is set to leave Paris Saint-Germain, and a reported loan enquiry for Aston Villa's Emiliano Martinez that was swiftly rejected, Amorim dismissed the need for new signings. "We showed we can beat any Premier League side, even a top team like Arsenal, where we were the better side," he said. "I'm delighted with our players and our three goalkeepers."

Amorim's confidence extends beyond the goalkeeping debate.

Speaking before the match, he expressed optimism about United's preparations, citing new signings like Matheus Cunha and Bryan Mbeumo as game-changers. "We're ready to win against Arsenal," he had said. "We've trained hard, and players like Cunha can shift the momentum in an instant."

Despite the defeat, Amorim believes United are on an upward trajectory after finishing 15th last season. "We want to return to Europe," he added, targeting a top-six or seven finish.

Posts on X echoed Amorim's support for Bayindir, with fans and pundits noting his passionate defence of the goalkeeper.

United's official channels also highlighted the team's readiness for the season, quoting Bayindir before the match: "We're ready for every game now. We'll fight for our fans, and they must support us at Old Trafford."

As United prepare for their next challenge, Amorim's faith in his current squad, particularly his goalkeepers, signals a focus on stability and growth rather than transfer market solutions.

Altay Bayindir's blunder sparks Ruben Amorim's fierce defence in Man Utd's Arsenal defeat