The German international spent four years at Arsenal between 2012 and 2016, but only managed one goal in 10 appearances before being shipped out to Werder Bremen.
When asked by Sky Germany if Gnabry's goalscoring form can be classed as 'crazy', Muller responded: "Yeah. Arsenal are perhaps asking themselves that."
Since arriving at Bayern in 2018, Gnabry has registered 30 goals in 72 appearances, and he is now reportedly a target for Manchester City.
The 24-year-old's brace against Frank Lampard's side takes his total to 17 goals for the season in all competitions, including six in six outings in the Champions League following his four-goal rout against Tottenham Hotspur in the group stages. body check tags ::