Zlatan Ibrahimovic scored a bicycle-kick four minutes into his debut as Manchester United beat Galatasaray 5-2.
Ibrahimovic, 34, met Antonio Valencia’s cross with a typically athletic volley which bounced kindly into the net.
The Turkish side then bossed the remainder of the half and led thanks to goals from Sinan Gumus and Bruma.
But a much-changed United side were rampant after the break. A Wayne Rooney double, Marouane Fellaini header and Juan Mata goal sealed victory.
Jose Mourinho used 22 players and will leave Gothenburg with as many questions as answers as he ponders his starting XI for next Sunday’s Community Shield match which sees his FA Cup winners face champions Leicester at Wembley.
Ibrahimovic led the line in the first half, with Rooney behind him and Anthony Martial and Henrikh Mkhitaryan either side.
But half-time replacements Marcus Rashford, Ashley Young and Jesse Lingard looked far sharper and led to United’s revival after a sleepy first 45 minutes.
Rooney equalised with a clean volley from another Valencia cross before Rashford won a penalty with an individual run from near halfway, and captain Rooney converted.
Valencia then made another goal as Fellaini drifted a header into the corner and Mata – who was sold by Mourinho at Chelsea – collected Michael Carrick’s clever ball to slide in.
World Cup winner Bastian Schweinsteiger – one of nine players reportedly told that they can leave the club this week – did not feature.