The 2019 U.S. Open women's bracket has been cut from 128 players to a final four that includes Serena Williams, Elina Svitolina, Belinda Bencic and Bianca Andreescu.

Svitolina is the highest-ranked player (No. 5) still in the field. The Ukrainian has already had her best showing at the U.S. Open by advancing to the semifinals, but she's still chasing her first Grand Slam title.

In fact, going by Grand Slam wins, Williams entered the quarterfinals with a huge advantage over the rest of the field:

Williams is attempting to win the U.S. Open for the first time since 2014. The five-year winless streak is her longest active drought at any of the four Grand Slam tournaments.

2019 U.S. Open Women's Semifinals (Thursday)

No. 5 Elina Svitolina vs. No. 8 Serena Williams, 7 p.m. ET

No. 13 Belinda Bencic vs. No. 15 Bianca Andreescu, 9 p.m. ET

Watch: ESPN

Live Stream: USOpen.org

From this group of semifinalists, Williams is the only one with a Grand Slam title on her resume. Svitolina has never reached the final in any of the four major tournaments. She made it to the semifinals at Wimbledon earlier this summer before losing in straight sets to eventual champion Simona Halep.

Svitolina has been close to flawless so far in the tournament. She hasn't dropped a set in any of her first five matches, and her fourth-round win over Madison Keys was her first against a top-10 opponent in a Grand Slam:

Williams also seems to have hit her stride heading into the showdown with Svitolina. Since dropping the opening set in her second-round match to Catherine McNally, the six-time U.S. Open champion has won eight straight sets. She needed just 44 minutes to get past Qiang Wang in the quarterfinals.

Per Wayne Coffey of USA Today, one big key to watch for in the Williams-Svitolina match is how well Williams' serve is working: "Her serve remains the greatest weapon in the sport; she has been broken three times in 46 services games at the Open, and won 79 percent of her first-service points."

Svitolina doesn't anticipate making any significant changes to her game as she attempts to defeat Williams, via David Kane of WTA Tennis:

"It's about the small details. You have to believe. You have to trust your game. You know, we are in the top of the women's tennis, and everyone can hit the ball over the net. Everyone can play three, four, five, six balls over the net. So you have to find the way to be consistent, find those small opportunities, and take them."

Williams owns a 4-1 advantage in five head-to-head matches, but Svitolina won their last meeting in the third round of the 2016 Olympics.

Bencic has already cleared one major hurdle in the tournament by knocking off No. 1 seed and defending champion Naomi Osaka in the fourth round. The Switzerland native has seemingly been building toward this moment her entire career, dating back to 2015 when, at the age of 18, she stunned Williams and Halep to win the WTA Rogers Cup.

Injuries have slowed down Bencic's rise, but this is the first time she's started to look like the phenom who reached the U.S. Open quarterfinals in 2014.

Standing in the way of Bencic and her first Grand Slam final is Andreescu, who is the hottest player on the men's or women's side with 11 straight match wins dating back to the Rogers Cup.

Andreescu has already had a successful 2019 season with three singles titles at the age of 19. Adding a U.S. Open title to her resume would be both the cherry on top of an outstanding year and a potential signal she is ready to challenge for the No. 1 spot in the world rankings in 2020.