In the first round of the Champions League quarter-finals in the early morning, Manchester United lost 1-2 to Sevilla and missed the quarter-finals. Manchester United only won once in the Champions League knockout after retiring from Sir Alex Ferguson.
Sir Alex Ferguson retired after the 12/13 season. In the following four seasons, Manchester United only played 6 times in the Champions League knockout. Only one victory was achieved. The Red Devils coach was Moyes.
Ferguson's retired Manchester United Champions League elimination record:
13/14 Season 1 Final Round 1 Manchester United (Offers) 0-2 Olympiacos
13/14 Season 1/8 Final Round Manchester United (Main) 3-0 Olympiacos
13/14 Season First Quarter Finals Manchester United (Main) 1-1 Bayern
13/14 season quarter-finals second round Manchester United (offer) 1-3 Bayern
17/18 Season 1/8 Finals First Round Manchester United 0-0 Sevilla
17/18 Season 1/8 Final Round Manchester United (Main) 1-2 Sevilla
In the 1314 season, if Moyes isn't an injured Rooney, I think that season can go even further.