The 1977–78 season was Manchester United's 76th season in the Football League, and their third consecutive season in the top division of English football, it was their first season under the management of which English football manager and player? 
1977–78 Manchester United F.C. season:  It was their first season under the management of Dave Sexton, following the dismissal of Tommy Docherty in the close season due to revelations about his personal life.
i don't know