Manchester United suffered a distressing second half on Tyneside, not only losing 4-1 but also seeing Joshua Zirkzee forced to leave the field due to injury.
The Reds had competed well in the first period, even though head coach Ruben Amorim understandably made changes, five in total, ahead of Thursday's Europa League quarter-final second leg.
Altay Bayindir and Harry Amass made their Premier League debut and first start respectively, with Andre Onana not in the matchday squad and a lot of experience left on the bench.
The hosts, without manager Eddie Howe who was hospitalised on Friday, went ahead through Sandro Tonali, only for Alejandro Garnacho to level before the break.