Serena Williams moved on to the U.S. Open quarterfinals after defeating Kaia Kanepi 6–0, 4–6, 6–3 on Sunday.
Williams defeated her sister Venus in the third round of the 2018 U.S. Open on Friday, winning 6–1, 6–2. She built on the momentum and was dominant in the first set against Kanepi, which she won 6–0 in just 18 minutes. It's the fastest set thus far in this year's U.S. Open.
Kanepi turned things around early in the second set, as Williams' serve speed dropped and Kanepi picked up her level. Kanepi took a 5-2 lead before Serena won the next two games, but Kanepi was able to even it up by winning the second set 6-4.
In the decider, Williams took an early 2–0 lead and held on to reach the quarters.
Kanepi defeated No. 1 Simona Halep in the first round.
Williams is looking for her 24th Slam singles title and seventh U.S. Open. It would be her first major since she won the 2017 Australian Open while pregnant with daughter Olympia.
Williams will face the 2016 U.S. Open runner-up and No. 8 seed Karolina Pliskova in the quarterfinals on Tuesday after Pliskova defeated Ashleigh Barty.