Gonzalo Castro scored twice and Pierre-Emerick Aubameyang and Ousmane Dembele were also on target as Borussia Dortmund thrashed Manchester United 4-1 in the International Champions Cup.

Dortmund had already played four pre-season friendlies before the encounter and Thomas Tuchel's men appeared noticeably fresher than United, who endured a difficult evening in Shanghai.

The Bundesliga side were 2-0 up by half-time thanks to Castro's scrappy opener and Aubameyang's penalty, before new boy Dembele scored a fine solo effort to stretch the lead after the break.

Henrikh Mkhitaryan, who joined United from Dortmund this month, scored his first goal for the club to reduce the arrears, but Castro's classy long-range finish re-opened the three-goal gap.

United, who had played just once before the encounter, were beaten for the first time under Jose Mourinho and lacked a sharpness in the final third that should improve as Mkhitaryan gets more game time, while Wayne Rooney and new arrival Zlatan Ibrahimovic are yet to play in pre-season.

Meanwhile, Tuchel can take plenty from Dortmund's performance and he still has Mario Gotze - who re-signed from Bayern Munich this week - and Andre Schurrle to integrate into the team.

The opening exchanges had all the hallmarks of a friendly encounter with little action of note, and Dortmund's first goal was typically scrappy. 

Sam Johnstone failed to adequately deal with Aubameyang's tame free-kick and, although the goalkeeper saved Dembele's follow-up, Castro scooped home the rebound.

Jesse Lingard fluffed a one-on-one as United sought a quick response, and Dortmund went 2-0 in front when Aubameyang sent Johnstone the wrong way from 12 yards after Antonio Valencia was penalised for handball in the area.

Johnstone prevented a deft chip from Aubameyang shortly before the break, but it was 3-0 in the 57th minute when Dembele finished a fine run by leaving Marcos Rojo flat on his back and lashing into the right-hand corner from the edge of the box.

United pulled a goal back when half-time substitute Marcus Rashford cleverly dummied for Juan Mata, who laid on for Mkhitaryan to tap in.

Mourinho did raise a cheer from the crowd with a classy backheel when retrieving the ball, but it was Dortmund celebrating again four minutes from time when Castro fired a 25-yard effort into the top left-hand corner to round off the win.