And coming through the hardest season the Gunners and their boss have experienced has made them stronger, not weaker.
The Arsenal captain had played just 37 minutes of first-team football since April last year but was chosen to lead the team out at Wembley, repaying the faith with a man-of-the match performance.
But that belief is a two-way street. “The most important thing, as you can see with my example, is the trust he gives to his players,” said Mertesacker.
“That is the most important part as a manager, being able to challenge your players but also trust them when you send them on to the field.
He has been calm and quiet as he has always been when dealing with those situations
Per Mertesacker on Arsene Wenger
“He has been calm and quiet as he has always been when dealing with those situations. I have to just give him credit for that because there were a lot of people saying he can’t deliver anymore but still his team is able to do that.
“It was just the right answer – even though it wasn’t about giving an answer to all the doubters – in those key moments and when the stakes are high in such a final when you can perform like that it says a lot about the team and how we grew even when there were difficult times this year.”
Having sat for most of the season on the sidelines, it has given Mertesacker more perspective on the narrative of the season.
Alexis Sanchez and Per Mertesacker's hilarious interview Sun, May 28, 2017
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Per Mertesacker was a towering presence during his post-match interview…
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“When you go through that period when you struggle you find it hard to win games and all the other teams have a go at you and you lose more than you win, you certainly doubt,” he said.
“But this team, in my opinion, grew at that time the most. We have still a lot to prove and this team wants that challenge especially next season.
“It is going to be a tough one again but I’m not frightened to say we have still a good chance in the league because this team suffered a lot this season and were still able to perform like that.
Arsene Wenger has won the FA Cup more times than any manager in history
“Consistency was not our strength – that is something we need to work on. But we are still able to have such big performances.”
Alex Oxlade-Chamberlain, meanwhile, refuses to accept that the players have been affected by uncertainty over Wenger’s future.
“As players it’s our job to deal with adversity and the manager’s future, players’ futures and shrug them off,” said Oxlade-Chamberlain.
“But I’m not going to stand here as a player and say that’s been an excuse for our lack of form. As a team we’re all professionals and every time we go out on to the pitch we are there to win and we can’t blame any of that for our lack of form throughout the whole season.”