LONDON, Great Britain - Wildcards Harriet Dart and Jay Clarke continued to mow down seeds on the Wimbledon lawns - this time defeating the No.1 pair of Gabriela Dabrowski and Mate Pavic 6-3, 6-4 to move into their first major quarterfinal.

The young British duo had taken three sets to overcome their previous two opponents, Yang Zhaoxuan and Robert Lindstedt in the first round and veteran No.13 seeds Kveta Peschke and Max Mirnyi in the second. (By contrast, Dabrowski and Pavic were playing their first match of the tournament, having received a first-round bye and a second-round walkover from Lyudmyla Kichenok and Artem Sitak.) Yet against a pair who have reached both Slam finals this year already together, lifting the Australian Open trophy, Dart and Clarke barely put a foot wrong.

19-year-old Clarke came out swinging, striking quickfire winners both off the ground and at the net to take the play entirely out of the Canadian-Croatian team's hands. With Pavic's serve largely untouchable - the 25-year-old would drop just three points on his delivery all match - the Britons targeted Dabrowski ruthlessly. Going all out on return, the local favorites broke the doubles World No.9 in three of her four service games.

Though Dart took slightly more time to warm up than her partner, offering up too many second serves in her first service game that were duly punished by the top seeds, once the 21-year-old had found her groove she was able to complement Clarke efficiently. With the second set break in hand, Dart was able to save three break-back points across her next two service games, finding ways to neatly neutralize Pavic's power.

With Dabrowski unusually unable to impose herself at net and Pavic lapsing into error on putative putaways, it was the wildcard team playing their first event together who kept their heads all the way to the finishing line. As Clarke served for the match, the penultimate 30-30 point proved crucial: one of the finest of the match, Dart ended it by coolly slotting a backhand past Pavic down the line.

It was the second upset of the day after No.11 seeds Nicole Melichar and Alexander Peya had squeaked into the quarterfinals past No.6 seeds Andrea Sestini Hlavackova and Edouard Roger-Vasselin 7-6(5), 4-6, 9-7. Over two hours and 15 minutes, the American-Austrian duo would slam nine aces between them in a serve-dominated affair, showing excellent athletic teamwork to take advantage of their rare opportunities.

In a marathon final set, just one break point came and went until the 15th game, in which Melichar staved off two break points - one with a Peya stop volley, the next with a service winner - before the 24-year-old held with a pinpoint lob. As is so often the case, missed opportunities on return would reverberate on serve: Sestini Hlavackova and Roger-Vasselin lapsed into the kind of loose error they had avoided all match on the Czech's serve - and, on the first match point, a deep Melichar return was enough to elicit a shanked backhand into the net from Sestini Hlavackova.