The Bayern Munich forward moved to England with Arsenal in 2011 at the age of just 16, moving from VFB Stuttgart.
Gnabry was quickly promoted from the Gunners' under 18 team to the under 21s and soon made his debut for the full team in 2012, and made four appearances for Arsene Wenger's side that season.
In 2013/14 Gnabry really started showing his talent for the first team and made his first start against Stoke City in the September, before scoring his first goal just days later.
The German really showed his ability across 14 games that season and his highlights video really shows how good he was at such a young age.
Injuries kept the forward out of the first team for about a year and he was then sent on loan to West Bromwich Albion, managed at the time by Tony Pulis.
He played just once in the league before being recalled in the January. Following his return to Arsenal, Pulis claimed the winger wasn't at the level to play, "Serge has come here to play games but he just hasn't been for me, at the moment, at that level to play the games," the former Stoke boss said at the time.
"He's come from academy football and not played much league football. Does academy football really prepare players for league football? And we're talking about Premier League football here.
"As a manager you pick a team that's going to win a game of football. You pick your best team, you don't leave people out because you don't like them, because of this, that and the other."
Pulis has been mocked pretty much ever since for those comments, due to how things have gone for the forward since then.
He moved to Werder Bremen in August 2016, after refusing a new deal at Arsenal due to lack of game time, and after impressing there he moved to Bayern Munich.
The 25-year-old has played 121 times for the Bundesliga champions, scoring 46 goals in the process, and has won two league titles, the Champions League and the FIFA World Club Cup in his time there so far.
Arsenal fans will look on and wonder what might have been!
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