Serena Williams hasn’t been crowned a champion since becoming a mother. But the way she’s rolling this U.S. Open, that could change.

Two years to the day after giving birth to her daughter Olympia, Williams shrugged off a rolled right ankle Sunday to dominate Petra Martic 6-3, 6-4 and reach the quarterfinals in Flushing Meadows.

“Ankle, I usually know if it’s horrible early on. I mean, I had a really bad ankle sprain in January. I was like, instantly, ‘No, this can’t happen. I’m finally healthy,’ ” Williams said. “But I’ll see [Monday]. So far I’m good. I’ve been managing it. We’ll see.”

Unlike when she twisted her left ankle in her Australian Open quarterfinal loss — when she foolishly declined to call for a trainer, and failed to win a single point on her serve the rest of the match — this time she quickly got a wrap put on her already-taped ankle. Then she wrapped up the win over Martic in short order.

“Yeah, I definitely wanted to have a better plan. I probably should’ve seen a trainer in Australia,” Williams said. “I definitely thought about that. … The first thing was like, ‘I’m finally healthy. The last thing I want is to have another bad ankle sprain.’ ”

With Williams moving on to play No. 18 Wang Qiang on Tuesday, her coach Patrick Mouratoglou didn’t seem overly alarmed.

“The ankle looks OK. She doesn’t feel much pain. It’s acceptable,” said Mouratoglou, who did caution, “We will know [Monday] when it’s going to be cold.”

Williams needed just an hour-and-a-half to dispatch Martic. And with the women’s draw opening up — No. 16 Johanna Konta plays No. 10 Madison Keys or No. 5 Elina Svitolina in the other bottom-half quarterfinal — a finals rematch with defending champ Naomi Osaka is looking more and more likely.

In the 2018 U.S. Open, a year after labor, Williams said she would be more kind to herself in terms of expectations. But she’s clearly moved the goalposts back to their usual lofty position.

“I feel like in this tournament, I’ve definitely turned a different zone,” Williams said. “I’m not sure if I can articulate what zone that is. But it’s not about kind, it’s not to myself, it’s not about anything in particular. It’s definitely something different, though.”

Only three mothers have ever won a Grand Slam final, but Williams’ path is set up for her to be favored to be the fourth. That’s clearly her mindset, which would tie Margaret Court’s all-time mark of 24 Grand Slam singles titles.

Since returning from childbirth, Williams has fallen in the Wimbledon final twice. She also lost last year’s U.S. Open final that included controversial calls, her eruption at the chair umpire and boos from the fans.

“It’s important that she’s coming back from being a mother. You can’t come back in the same shape as before in a few months. It takes time,” Mouratoglou said. “I never had a baby, but … you know it’s a big thing, a big transformation for the body. It’s also a new responsibility, so it takes time to come back to the person you were before.

“She was feeling guilty — she was feeling that the baby needed her a lot because a young baby is very weak, and as a mother you feel like you need to be here all the time to protect the baby. Whenever she was not here because she needed to practice or play, she was feeling guilty. The first months it was hurting her a lot.”