Manchester United midfielder Ander Herrera has admitted that his team struggled against a "fitter" Borussia Dortmund in Friday's pre-season friendly in Shanghai.

Henrikh Mkhitaryan scored his first goal for Man United against his former club, but Dortmund ran out 4-1 winners during what was an impressive performance from the German outfit.

Herrera was not keen to offer up excuses after the match, but has insisted that tiredness played a factor due to Dortmund being a few weeks ahead of Man United in their preparations for the new campaign.

"They are a very good team and they have already played four pre-season games. They are fitter and better, but there are no excuses. Man United should never lose," Herrera told MUTV.

"When you have four or five games, you arrive one second before opponent. We do not want to use excuses, but they are a very good team. We are improving and building a fantastic team. We are optimistic for the new season.

"We are a team. We want to be fit as soon as possible. We want to be ready for Leicester [in the Community Shield]. We want to have the ball and attack and I think we are going to see a very offensive Man United, but a compact team as well."

Next up for Man United is a clash with rivals Manchester City in Shanghai on Monday.