LONDON, July 4 — Madison Keys celebrated Independence Day on Saturday by upsetting sixth seed and last year’s runner-up Amanda Anisimova 3-6 6-2 6-3 in an all-American third-round battle on Centre Court at Wimbledon.

But there was no joy for U.S. sisters Venus and Serena Williams who pulled out of their much-anticipated doubles match because ⁠of Serena’s knee injury.

The New Jersey-born Anisimova looked in fine form at the start of the match and produced a ⁠big serve that Keys could only dump into the net to win the first set in warm afternoon sunshine on Centre Court.

But that serving weapon, which earned her 20 aces in the last round to beat another American, Sofia Kenin, failed to fire in the second set on Saturday. She ⁠had trouble with the toss and suffered breaks in the second and eighth games.

Keys, whose best performances at Wimbledon are two quarter-final appearances but who won the Eastbourne warm-up ⁠tournament on grass last month, grew in confidence and consistency.

The 26th seed, last year’s Australian Open champion, won 76% of points on her first serve and produced 23 unforced errors to the 24-year-old Anisimova’s 42.

A magnificent backhand pass secured her a break of serve in the fourth game of the decider and she won the match with a serve that Anisimova put wide.

Keys was one of eight ​American singles players working hard in southwest London ‌on the 250th anniversary of the Declaration of Independence, while their compatriots at ⁠home enjoyed a day off with festivities and fireworks.

Ashlyn Krueger, ​ranked a lowly 102 in the world, ⁠moved into the last 16 ⁠with a comfortable 6-3 6-2 win over Ukraine’s Daria Snigur.

Two other Americans were knocked out in early matches on Saturday. Emma Navarro, the 23rd seed, was beaten 6-2 4-6 6-1 by fast-improving 12th seed Marta Kostyuk of Ukraine.

In the ⁠men’s draw, 23-year-old Zachary Svajda, on his Wimbledon debut, managed to take a set off fifth-seeded Australian Alex de Minaur ‌before bowing out 6-2 ⁠5-7 6-2 6-4.