Gylfi Sigurdsson's brilliant free-kick put a dent in Manchester United's Champions League hopes as yet another Old Trafford draw gave relegation-threatened Swansea reason to believe in Premier League survival.
England striker Marcus Rashford's contentiously-won penalty just before half-time, converted by Wayne Rooney, had given United control of the match but Sigurdsson bent the ball home the 79th minute, seconds after Ander Herrera abandoned the post to join the wall.
It was a deflating way for United to set a new record unbeaten streak - 25 matches dating back to October 23 - and a more important statistic is the 14 league games they have drawn this season, 10 in front of their own fans.
And if that was not enough there was further bad news for United's overworked medical staff, with Luke Shaw and Eric Bailly picking up injuries to join a cluttered treatment room.
Mourinho, already missing a host of first-teamers, made four changes from Thursday's derby draw against Manchester City, with Rooney, Jesse Lingard, Ashley Young and Shaw recalled.
Hit play on the video above to see the match highlights.