The England youth international was harshly shown a straight red card early in the second half for a dubious foul on Katie Stengel who put the champions-elect ahead from the spot.
The Black Cats valiantly fought on but late goals from Yana Daniëls and Missy Bo Kearns added to a score line which perhaps flattered the hosts.
With Grace McCatty serving the last of her three-match ban and midfielder Emma Kelly recovering from an ankle injury, it was once again a youthful side that took the field at Tranmere Rovers’ Prenton Park.
Speaking to the Echo in midweek, Mel Reay said her side had ‘nothing to lose’ and that’s exactly how they started as Keira Ramshaw blasted over and then tested Rachael Laws from distance.
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Liverpool fired back with chances of their own – good build up play from Daniëls finding Taylor Hinds on the edge of the box who shot wide before Rachel Furness tried her luck with a rising drive that cleared the bar.
But the visitors were a threat on the break, a good ball finding Emily Scarr who cut inside and fired towards goal, but her effort was deflected for a corner.
The former Black Cats’ opposite number Alison Cowling was then called into action to deny the Reds in quick succession, saving first from Niamh Fahey and then clawing out Rhiannon Roberts’ header. In stoppage time, Neve Herron was in the right place to clear Hinds’ freekick off the line.
Reay’s would have been delighted by the performance, especially after several difficult weeks, but any hopes of building on their sold first half display were shattered within minutes of the restart when Liverpool were awarded a penalty.
Stengel was adjudged to have been tripped in the box by Herron – who was given her marching orders – and after a short delay as Sunderland argued their case, the American forward stepped up and beat Cowling high into the net.
Despite a half chance at the near post for Abbey Joice following a sharp move involving Farrugia and Scarr, the Black Cats were forced to fight a rear-guard action as the Reds pushed forward looking for more goals.
A long ball into the box from Hinds was spilled by Cowling but Louise Griffiths reacted well on the line to block Melissa Lawley’s turn and shot. Leanne Kiernan and Hinds both missed good opportunities to extend the lead before the killing blow arrived with five minutes remaining.
The Sunderland defence failed to properly clear Megan Campbell’s long throw, with Stengel setting up Daniels to neatly pass the ball past Cowling and into the net.
Referee Lucy May pointed to the spot for the second time for a foul on Stengel and No substitute Kearns made no mistake as the found the bottom corner.
A frustrated Sunderland will likely appeal Herron’s red card with the international break giving them time to regroup before facing Crystal Palace in their rearranged fixture in a fortnight’s time.
Sunderland: Cowling; Brown, Beer, Herron, Griffiths; Ramshaw (c), McInnes, Joice, Scarr, Manders; Farrugia.
Subs: Moan, Boyes, Mullen, Blakey, Ede, Watson, Burt.