The men's quarterfinals and women's semifinals took place on Friday at Indian Wells, with Venus Williams and Juan Martin del Potro among those in action.
Williams suffered defeat to Daria Kasatkina, while top-ranked Simona Halep lost to unseeded Naomi Osaka. It means two 20-year-old outsiders will contest the final.
Meanwhile, Federer learned his opponent for the last four as Borna Coric made it through. Milos Raonic and Juan Martin del Potro will contest the other semi-final on Saturday.
Below, we'll take a look at the day's results and preview Saturday's action.
Women's Friday Results
No. 20 Daria Kasatkina def. No. 8 Venus Williams: 6-4, 4-6, 5-7
Naomi Osaka def. No. 1 Simona Halep: 6-3, 6-0
Men's Friday Results
No. 32 Milos Raonic def. No. 18 Sam Querrey: 7-5, 2-6, 6-3
No. 6 Juan Martin Del Potro def. No. 31 Philipp Kohlschreiber: 3-6, 6-3, 6-4
Osaka caused a major shock as an unseeded player who destroyed World No. 1 Halep. The Romanian simply had no answer for Osaka's ability to wreck her service game.
In all, Osaka forced five breaks, per the WTA official website. The same source also noted how Osaka "saved four break points in the final game of the match in a game that went to six deuces, but clinched victory on her third match point as Halep buried a backhand in the net."
The ability to frustrate Halep proved crucial for the player ranked 44th in the world. However, in Kasatkina she will face a player already well-versed in upsetting more established talents.
She repeated the trick on Friday by surviving an epic three-set marathon against decorated veteran Williams. The 37-year-old rallied to take the second set, before young Kasatkina proved her powers of recovery by winning the third to reach the last four.
Before beating Williams, the Russian had seen off Angelique Kerber in comprehensive fashion, winning 6-0, 6-2. Prior to her win in the last eight, Kasatkina beat both Sloane Stephens and Caroline Wozniacki.
It means she has beaten the winners of the last four Grand Slams, according to Christopher Clarey of the New York Times.
Clarey also noted some of the qualities behind Kasatkina's winning run: "She does have power, as anyone who has watched her rip a topspin forehand can attest. But she also has a wide array of solutions and strokes, including wicked drop shots, and a gift for rhythm shifts that borders on the musical."
Whether Kasatkina will be able to raise her game against an opponent nowhere near as illustrious as her recent vanquished foes will be one of the many fascinating sub-plots of this final.
Saturday's semifinals are now set after Friday's results, with No. 1 Roger Federer set to battle Borna Coric and Raonic taking on Del Potro.
Federer, obviously, will be the prohibitive favorite against the 21-year-old Coric. Federer won the only matchup between the two in 2015 and has won every match thus far this season, going a cool 16-0 with titles at the Australian Open and Rotterdam Open.
He's doing all of this at the age of 36. It's kinda ridiculous, though at some point Federer expects to be supplanted.
"The young guys are still calibrating their game, understanding what they need to do. They are still working on a lot of things," he said on Thursday, per Helene Elliott of the Los Angeles Times. "So there is a lot on the plate for them, but they will learn and they'll get better and eventually push us out and that will be the end from us. Pretty simple, right? That's just how life is."
But nobody's pushing Federer out anytime soon, it would appear. And given the way he is playing right now—he hasn't dropped a set this tournament—a Coric upset feels borderline inconceivable.
Raonic vs. Del Potro is harder to call. Raonic holds a 2-1 advantage in the series and won their most recent matchup in 2017 at the Delray Beach Open.
Del Potro is having the better season, however, currently holding a 15-3 record and a Mexican Open title. Raonic has struggled, on the other hand, going just 5-3 this season, which included a first-round loss at the Australian Open.
Recent form would favor Del Potro, who knows he likely will have to go through Federer to win a title.
"I'm not thinking about that," he said when asked about a potential meeting with Federer, per Mikael McKenzie of the Express "I just want to keep winning. It's good to me feel with this confidence when I getting to the court and I play well, but I'm going step by step. Of course any chance to play with Roger would be great."
Look for Del Potro to beat Raonic and get his shot at dethroning the hottest player in tennis.
The women's results and preview will be updated after Friday night's semifinal matches conclude.