Mikel Arteta heaped praise on Hector Bellerin for turning around his Arsenal career after impressing in Sunday's Premier League win over Sheffield United.
The 25-year-old right-back was linked with a move away from the Emirates Stadium earlier in the summer having struggled for consistency and injuries.
It was one was of his best performances of recent times as he continues to get back up to speed following his latest injury setback.
Arteta has plenty of options at right-back with Cedric Soares and Ainsley Maitland-Niles also available to the Arsenal boss.
But he has been pleased with Bellerin's commitment to getting back to his best and his willingness to improve.
"There are no secrets," Arteta said of the three-capped Spain international.
"He's demanding all the time to do more individual work, to improve in the final third.
"He's doing a lot of reviews, a lot of individual defensive work as well in things that he has to improve. When you do that, you get rewarded.
"Maybe it's not going to happen in the first week or the first month but over time, he'll improve.
"He had a difficult period because he was doubting himself in his head with the amount of time that he's been here, a lot of things have been happening in the background.
"I trust him, I know him really well and I know how much he can still improve. He's showing every day that he's willing to do it. I'm pleased because I really like him.
"I understand that after such a long time at the club, and a lot of things that happened in that trajectory of his development, that he doubted whether he was still OK to continue here, what ambitions he had here, how he can evolve here."
Meanwhile, Sheffield United boss Chris Wilder said referee Lee Mason made a mistake to not send off Arsenal's David Luiz after he pulled back Oliver Burke in the opening stages.
"He has got to show courage, there are five of them (officials) making a decision," Wilder said.
"He has pulled his shirt, I am not making things up or clutching at straws, he has pulled his shirt. Regardless of if he rips it off his back or pulls it, the right decision has to be made.
"I'm going to be annoyed and frustrated about it. Are we looking for small wins that might help us? I'm saying now David Luiz should have been sent off."