A crowd of 15,387 - a Barclays Women's Championship record - saw Lumsden's fine first half finish give Becky Langley's side the lead on Wearside, and her second after the break, which came direct from a corner, put the visitors firmly in control.
Emilly Scarr pulled one back for the hosts late on but it wasn't enough, with the Magpies holding on to take the three points on the first meeting between the two local rivals in the second tier.
Backed by a superb United crowd who had made the trip to the home of the Black Cats, this was an occasion to savour for those in black and white, and Serena Taylor and Michelle Mercer were there to capture the best of the action for this newcastleunited.com gallery.