Arsene Wenger has expressed his frustration that Arsenal did not see the best of Serge Gnabry.
By scoring twice in Bayern Munich's 3-0 victory over Lyon on Thursday (AEST), Gnabry took his goals haul to nine in this season's Champions League.
Gnabry could be a star of Monday's final against Paris Saint-Germain, and may consider the great strides he has taken since returning to Germany as confirmation he was right to leave Arsenal.
His exit at the age of 21 in August 2016 came just weeks after then Arsenal boss Wenger went on the record as saying he hoped Gnabry would commit to the Gunners for the long term.
Instead, Gnabry chose the option of joining Werder Bremen, before switching to Bayern 10 months later.
"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.
"We had an agreement with him you know. 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-21s, and Bayern made a deal with Werder Bremen.
"He wanted to sign in the end, he didn't want to extend the contract [with Arsenal].
"I was very sad we couldn't get over the line with him because I knew he would have a great [career].
"He can be a number 10, he can be a number nine, he's a very intelligent player."
Wenger added: "He's creative, he can score goals right-footed and left-footed, good power, good penetration, very, very clever with the timing of his runs.
"His tendency was a bit too easy... but he has matured a lot and he's one of the dominant players now in Germany."