Between his appointment on Monday and his first game in charge, away at Leicester City on Saturday, Marsch has just five days to prepare his players to take on the first of 12 crucial Premier League games in the fight for survival.
The Whites are two points clear of the drop zone and haven't won a league game since United's 3-2 victory over West Ham on January 16.
The American coach will need to act quickly to turn around a team that are struggling for form and hugely under-performing defensively.
On Thursday, the club announced that Cameron Toshack and Franz Schiemer will be joining Marsch on the first-team coaching staff, while Mark Jackson will take the step up from Under 23s coach to help Marsch out.
Here are 21 pictures from the open training session which Marsch held at Thorp Arch on Thursday: