Bruno Fernandes fired a dramatic injury-time winner at Old Trafford to sink Rangers and push Manchester United to the brink of automatic qualification for the Europa League round of 16.
A 2-1 victory in the Battle of Britain tie lifted United into fourth place in the table and means a point against FCSB in Bucharest next week should be enough to clinch a top-eight finish and avoid a two-legged play-off.
It also brought much-needed relief for head coach Ruben Amorim following his emotional reaction to Sunday's defeat to Brighton when he labelled his team perhaps the worst in United's history.