Erik ten Hag and his coaching staff were eager to mix in the fresh talents, assess them, and give them first-team experience.
It was a busy session, with many under-21 players brought up to train with the first squad.
Marc Jurado (above), a young defender, was among the teenagers called up to train with the first team group.
Marc Jurado among Manchester United youngsters called up to first-team training
Manchester United welcomed Antony and Martin Dubravka to their first training session on Friday.
The former Barcelona right-back has captained the under-18 side and recently stepped up to the under-21s, scoring his first goal against Everton a fortnight ago.
Antony was seen below with Shola Shoretire, Omari Forson, and Dan Gore.
Kobbie Mainoo, Isak Hansen-Aaron, and Zidane Iqbal were also involved. Iqbal had impressed earlier this week in a win for the under-21s over Carlisle.