Pierre-Emerick Aubameyang scored twice as Borussia Dortmund put a dent in AC Milan's hopes of an rapid revitalisation on Tuesday, easing to a 3-1 victory in the International Champions Cup.

Milan have been one of the most active sides in the transfer window with 10 new faces through the door since they finished the 2016-17 Serie A campaign in sixth.

Ricardo Rodriguez, Franck Kessie and Fabio Borini all started the opening game of the friendly tournament, with Hakan Calhanoglu and Mateo Musacchio half-time entrants.

They all started last week's 4-0 exhibition win over Lugano but were unable to bring about a positive result this time, the Rossoneri comfortably beaten by Peter Bosz's side in China.

Nuri Sahin grabbed the opener for Dortmund with a crisp, low strike before Aubameyang doubled their lead from the penalty spot.

Carlos Bacca pulled one back for Milan but Aubameyang's second completed the victory for Dortmund, while Vincenzo Montella will be desperate to incorporate more of his new stars to try and turn their fortunes around.

Dortmund flew out of the blocks in extremely wet conditions in Guangzhou with Ousmane Dembele threatening the Milan goal twice in the early exchanges.

And it was not long before the Bundesliga side were ahead as Sahin opened the scoring with a low, 16th-minute strike that Marco Storari should have done better with, the ball squirming under his outstretched hand.

Things went from bad to worse for Montella's side moments later when Gabriel Palletta was adjudged to have fouled Christian Pulisic in the penalty area, Aubameyang making no mistake from 12 yards.

Milan eventually posed an attacking threat midway through the half and Bacca reduced their deficit with a surprise outside-of-the-boot strike that caught Roman Weidenfeller cold, his effort skidding beyond the goalkeeper.

After a drinks break, Dortmund resumed their dominance and Gonzalo Castro should have re-established their two-goal cushion before the interval after excellent work from Aubameyang.

Montella introduced Musacchio and Calhanoglu at the break and although the Italians initially looked better they soon found themselves further behind.

Dortmund's third goal came after Calhanoglu wasted a free-kick and then a corner, the Bundesliga outfit launching a swift counter-attack through Castro.

Having carried the ball the length of the pitch the midfielder found Pulisic, who rolled it into Aubameyang and the Gabon international had the simple task of tapping home.

Aubameyang departed minutes later as Bosz entirely changed his front three, Alexander Isak replacing the match winner, while Mario Gotze and Emre Mor also stepped off the bench.

Instead it was Milan who came closest to adding to the scoreline, but Patrick Cutrone was denied by the feet of substitute goalkeeper Dominik Reimann when one-on-one.

His wastefulness summed up Milan's disjointed performance, while Bosz will be pleased with how his Dortmund side are developing.