Gerard Deulofeu came off the bench to spark an incredible comeback as Watford beat Wolves 3-2 to set up an FA Cup final against Manchester City.
Deulofeu scored from a tight angle with a shot past Arsenal goalkeeper Wojciech Szczesny just four minutes after Mesut Ozil put Arsene Wenger's team in front from close range.
Deulofeu scored 18 times in 33 matches for Barcelona's B side last season and also made a handful of substitute appearances for the Spanish champions.