A hat-trick from Sunderland's Mikael Mandron dumped City EDS out of the U21 Premier League Cup on Friday night.
City went down to a 4-2 defeat at Spotland, despite holding the lead twice.
Sinan Bytyqi gave Patrick Vieira’s side the lead after midway through the first-half with a goal that was cancelled out by Mandron’s first goal of the night .
Olivier Ntcham restored the home side’s lead five minutes into the second half before Mandron scored twice on 62 and 66 minutes to put the Wearsiders in control.
18 minutes from time, Watmore scored a stunning fourth goal for the Black Cats to confirm their progress into the next round.
