Hours apart on Arthur Ashe, the sisters who have done as much as anyone — including Billie Jean King — to change the face of tennis took their first steps toward what could become a third-round U.S. Open confrontation.

First of the Williams Women, Venus survived a three-setter against Svetlana Kuznetsova 6-3, 5-7, 6-3. Next, under the lights and after Kelly Clarkson served as her opening act, Serena overpowered the overmatched Magda Linette 6-4, 6-0 in her return to New York after missing last year’s tournament because she was busy having a baby.

You probably heard about that. Probably heard about the life-threatening complications that followed the Sept. 1, 2017, birth of Alexis Olympia. Probably heard about the physical and emotional obstacles Serena Williams has overcome to return to big-time tennis and the Open.

This six-time Open champ and 23-time Grand Slam winner has become a champion of all moms as she navigates the tricky and challenging path of parental and professional obligations that confront all of us with children, not only mothers. No one chooses to miss a birthday party, a school play or a youth hockey game. We make do as best we can.

“I’m still learning to put a mask on myself,” Serena the career wome

n said during her post-match interview, in which she offered a minimum of introspection. “Almost in a way, it’s good for me.”

The victory over Linette marked Serena Williams’ 18th match of the year in only her seventh tournament. Seeded 17th — one rung lower than Venus — she is somehow deemed the favorite in this event. The path to the title opened a bit for her when top-seeded Simona Halep, who had shaped up as her prospective fourth-round opponent, was stunned in straight sets by Kaia Kanepi.

Still, though, there is much work to be done before Serena breaks the tie with Chris Evert for most Open championships in the Open Era and ties Margaret Court for the most Grand Slam titles of all time. But Monday’s second set, in which she moved well and played with crisp authority, created cause for optimism.

“It’s never been easy to get to any point in my career, and this isn’t easy, either,” Serena said after the match, in which she never faced a break point while converting four of the six she held. “Right now, I feel I’m just on the road to getting better.”

Venus, who reached the semifinal here last year before going down to eventual champion Sloane Stephens in the third set, is 38 and in her 20th Open. Serena, who will turn 37 late next month, is competing in this event for the 18th time. The sisters have met four times previously here in Queens. Who knows how many more chances there will be for a fifth?

“Hopefully we’ll get there,” Serena said. “There are several matches to play before we get there.”

Two exactly, on Wednesday. There will be one for Venus against 27-year-old Italian Camela Giorgi and one for Serena against 23-year-old German Carina Witthöft.

“That’s the draw. I’ve had an interesting draw,” said Venus, who appeared enervated at different points of her victory. “Obviously the next match, my opponent is not going to roll over. That’ really my focus. Hopefully we’ll be there [in the third round].”

Serena wore a tutu with one shoulder exposed. Horrors! At least it wasn’t a catsuit. Lord knows whose sensibilities she might have offended had she walked onto the court in that attire. This, of course, is a reference to the French Open banning the catsuit Serena wore at Roland Garros this summer as the tournament moves to a more restrictive dress code for next year.

“One must respect the game and its place,” French Tennis Federation president Bernard Giudicelli said by way of an insulting explanation for the edict.

Racist, sexist or both? Take your pick.

Serena had no desire to do that.

“I don’t want to talk about that,” she said.

Venus, however, would and did.

“Serena has done so much for tennis, so much for tennis, so much for people in the world,” the big sister said. “I think that’s the only focus we can focus on.”

Both women have transcended their sport to become cultural icons in the way that sets them apart from their male contemporaries. Warriors on and off the court, refusing to be constrained by the 78-by-27 boundaries drawn by the white lines.

When Serena won this championship for the first time in 1999, two years before Venus, Derek Jeter was in his fourth season and Latrell Sprewell was leading the Knicks to the NBA Finals(!). Which is to say this is not going to last forever.

Savor the Williams Women while you can.