KEY BISCAYNE, Fla. (AP) — Maria Sharapova was happy to play an 11 a.m. match Monday, especially when her work day was already done by the time a mid-afternoon shower interrupted play.

“It’s nice to see all the players coming back in the locker room, and I’m like, ‘I’ll see you later,’” she said.

Sharapova started early but didn’t start well. She won only five points in the first four games before settling down to reach the quarterfinals at the Sony Open by beating Kirsten Flipkens 3-6, 6-4, 6-1.

Top-ranked Serena Williams had an easier time and eliminated fellow American CoCo Vandeweghe 6-3, 6-1. Williams could meet Sharapova in Thursday’s semifinals.

But Sharapova has been flirting with an early exit. She endured her second consecutive ragged three-setter, and found herself trailing 4-0 after only 15 minutes. Sharapova seemed thrown off by the lack of pace from Flipkens, a tour veteran who hits floating backhands and sometimes slices her forehand as well.