Arsene Wenger has revealed he was "very sad" when Serge Gnabry decided to leave Arsenal in 2016.
The German winger had joined the Gunners youth system in 2011 from Stuttgart but struggled to establish himself in the first-team with only 18 appearances to his name.
The now 25-year-old has gone on to star for the Bundesliga giants and scored a crucial double as Bayern defeated Lyon in the Champions League semi-finals on Wednesday, with Wenger quick to point out the performance of his former protege.
"Let's not forget Gnabry, I bought him at the age of 15 from Stuttgart and he was injured a lot," Wenger told beIN Sports.
"He's creative, he can score goals, right-footed, left-footed, good power, good penetration, very, very clever with the timing of his runs.
"His tendency was a bit too easy, like I've told you about with these young talented players, but he has matured a lot and is now one of the dominant players in Germany."
While Gnabry had yet to show his full potential in 2016 and was struggling with injuries, Wenger revealed he was desperate for the German attacker to remain at the Emirates.
"No, no, we had an agreement with him you know," Wenger said.
"I had given him out on loan to West Brom and he didn't play a game. He came back, he was injured. We worked very hard with him for six months and he went out with the German national team, under-21's, and Bayern made a deal with Werder Bremen.
"He wanted to sign in the end, didn't want to extend his contract (with Arsenal) and I was very sad. But we couldn't get over the line with him because I knew he would have a great career.
"He can be a number nine, a number 10...he's a very intelligent player."
Though Wenger was impressed by the performance of Gnabry against Lyon, the former Arsenal boss noted Bayern's defence must tighten up before facing Paris Saint-Germain in the Champions League final on Sunday.
"They were too open tonight to compete with Paris Saint-Germain," Wenger noted.