Mikel Arteta has revealed Gabriel Martinelli surprised Arsenal's medical staff after coming on and scoring the winning goal against Manchester City.
Forward Martinelli was initially not expected to be fit enough to feature at the Emirates Stadium on Sunday evening but defied advice to make the squad.
He then replaced the injured Leandro Trossard for the second half and secured all three points for Arteta's side at the death courtesy of his deflected strike.
His effort cannoned wickedly off Nathan Ake just minutes from time and propelled Arsenal joint-top of the Premier League table, level with fierce rivals Tottenham.