Fifth-seeded Elina Svitolina of Ukraine has already taken out one Williams sister. Now, she may have to get by another.

Svitolina, 24, is on to her first US Open semifinal, which is not a great surprise since she’s emerging from her first semifinal berth at Wimbledon in July.

With her chase-every-ball-down game, she swept past Britain’s 16th-seeded Johanna Konta in Tuesday’s quarterfinals on Ashe Stadium 6-4, 6-4.

That’s the same court Svitolina dispatched Venus Williams on in the second round. She could play Serena Williams, who goes against Qiang Wang on Tuesday night, in Thursday’s semifinal.

In the second-to-last point of her victory over Konta, Svitolina swept in to pick up a terrific forehand drop volley and backhanded it for a winner. That’s the type of get that could give Serena fits if there is a semifinal meeting.

“Definitely it’s a big challenge to play against her,’’ said Svitolina, who is dating tour veteran Gael Monfils.

“Obviously Serena is an amazing champion. She has a big serve. And that’s what I have to expect. I have to react quickly and try to take my chances when I have.”

They haven’t met in three years. Williams has a 4-1 record over the Ukranian but their last meeting at the 2016 Olympics was captured by Svitolina. Serena had beaten Svitolina months before at the 2016 French Open 6-1, 6-1. At the Olympics, Svitolina said she “was getting a lot of balls back.’’

“I think I have to run a lot and try to react,’’ Svitolina said of the upcoming meeting. “I played some big hitters in this tournament, a lot, and I have to just react quickly with my feet and with my shots. Then when I have the opportunity, go for it.”

After Venus lost to Svitolina, the elder Williams admitted she’s tough to play. Serena could have a focused scouting report.

“(Svitolina) always plays extremely well against me,’’ Venus said. “She can keep that form up and she’s got a lot of great things ahead of her. I think there are probably a lot of matches that are winnable for her that she hasn’t been able to win.”

Svitolina was surprised when asked what’s taken her so long to get to two straight Grand Slam semifinals.

“I don’t think it has been that slow,’’ said Svitolina, the first Ukranian women to get to a US Open semifinal. “I’m 24. It’s OK. I’m doing fine.’’

However, Svitolina, who turns 25 next week, admitted “consistency’’ in Grand Slams has been an issue, but she got a boost by winning the WTA’s season-ending championship in Singapore in late October.

“Mentally I’m handling the pressure points better,’’ she said. “(Singapore) gave me the belief I can play very consistent against top layers.’’

Svitolina admitted hitting against Monfils, the 13th seed, has helped. The French acrobat is still alive, playing in Wednesday’s quarterfinals vs. Matteo Berrettini. Monfils was watching from the Ashe stands.

“Now he’s got to step up,’’ she said during her on-court interview.