A six-time US Open champion, Williams navigated a tricky start to triumph 6-3, 6-1 after an hour and 10 minutes at Arthur Ashe Stadium, Flushing Meadows.

The American, who broke the Open Era record for grand slam titles at the 2017 Australian Open, has lost three grand slam finals since marrying and giving birth to daughter, Alexis Olympia, in September 2017.

It is all in the hope of tying Australian Margaret Court's all-time record of 24.

"It's really good," Williams, the former world number one, said.

"I mean, to be in yet another final, it seems honestly crazy.

"But I don't really expect too much less."

Svitolina was playing her second straight grand slam semi-final after reaching her first at Wimbledon in July.  

Though the Ukrainian trailed Williams 1-4 in their previous matches, she had won their most recent encounter at the Rio 2016 Olympic Games.

She started on the attack and engineered three break points in the opening game.

Williams saved all three and overturned a 40-0 deficit in the following game to earn an essential break.

After 16 minutes decided the first two games, Williams remained in control for the remainder of the opening set, saving three more break points and ultimately serving it out on her first set point.

Taking momentum into the second set, the number eight seed raced into a double break lead at 5-1 and converted her second match point on her 33rd winner – a backhand down the line.

Standing between Williams and glory on Saturday (September 7) is 15th seeded Canadian Bianca Andreescu, who defeated 13th-seeded Swiss Belinda Bencic to reach her first grand slam final.

Andreescu never held a break point in the first set, but won it in a tiebreak after saving all six break points against her, including one set point.

The 19-year-old then battled back from a double-break down in the second set to reel off the last five games and secure a 7-6, 7-5 victory after two hours and 12 minutes of play.

"I've always dreamt of this moment ever since I was a little kid," Andreescu said.

"But I don't think many people would have actually thought that it would become a reality."

Andreescu moves into the final on her US Open main-draw debut.

This time last year she was ranked outside the top 200 and fell in the first round of qualifying in New York City.

The rising star, who will make her first appearance in the top 10 of the Women's Tennis Association rankings on Monday (September 9), becomes the second Canadian to reach a Grand Slam final, following Eugenie Bouchard's run to the Wimbledon final in 2014.

She also becomes one of just seven women to make a grand slam final before their fifth appearance in a main draw, with this being her fourth.

The only previous meeting between Williams and Andreescu came in last month's Rogers Cup final, which ended abruptly after Williams was forced to retire due to an upper back injury while trailing 3-1.

US Open action continues tomorrow with the men's singles semi-finals.