The Black Cats fought bravely in a contest in which they more than matched their Super League opponents, with Keira Ramshaw’s close-range strike four minutes from the end of normal time cancelling out Veatriki Sarri’s first half opener.
And although they finished the game strongly, Whipp’s powerful header secured a narrow victory for the Blues and their place in Monday’s draw.
With two of her most experienced players missing – Grace McCatty suspended after seeing red in the defeat to Lewes and Emma Kelly rolling her ankle in the same game – head coach Mel Reay was forced to make changes for the trip to the Midlands.
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On a positive note, Faye Mullen returned to the starting XI after recovering from a hip injury and teenage forward Katy Watson, who signed from the Regional Talent Club on deadline day, was named on the bench.
The game quickly settled into a pattern of Birmingham seeing most of the ball and Sunderland working hard to close their opponents down and hit quickly on the break. It was an approach which almost paid off within the first 10 minutes as Maria Farrugia forced a good save from Emily Ramsay after cutting inside from the flank.
But it was the hosts who took the lead just before the half hour as Sarri worked the ball onto her left and unleashed a powerful shot into the top corner from outside the box.
Heading into half time, Birmingham had a flurry of chances as Lucy Quinn fired just over and then Claudia Moan stopped a close-range effort. She was called into action again moments later, tipping a 25-yard freekick around the post.
Moan, recalled in place of Alison Cowling, was proving to be an early contender for player of the match as her heroics helped her side survive an early scare after the interval. Sarri’s clattered the crossbar from distance which was still shaking when the stopper superbly parried Emily Whelan’s glancing header onto the post.
Then, Sunderland deservedly drew level. A mistake at the back saw Ramsay handle a goal-bound back pass six yards out and Ramshaw smashed the ball underneath the wall of blue shirts on the line and into the bottom corner.
As the game edged into seven minutes of stoppage time, Moan came to the rescue as she parried another header clear of danger.
Sensing the tie was there for the taking, Reay called on Watson – who has scored 27 league goals for the Regional Talent Club this season – at the start of extra time to provide a cutting edge in attack. However, their momentum was abruptly halted when Gemma Lawley’s pinpoint delivery was met by Whipp who looked marginally offside.
Moan once again kept Birmingham at bay in the second period, diving to her left to parry a long-ranged effort, and then denying Jade Pennock.
Sunderland: Moan; Brown (Blakey 106’) Beer, Herron, Griffiths; Mullen (Boyes 91’); McInnes (Ede 79’), Joice, Manders (Watson 91’), Ramshaw; Farrugia.
Subs: Cowling, Scarr, Burt, Blakey.