The scintillating surge by Danielle Collins continued at the Credit One Charleston Open on Saturday, as last week's Miami Open champion won her 12th straight match by knocking out No.3 seed Maria Sakkari 6-3, 6-3 in the semifinals.

"I think my aggressive game style helped me," Collins said after her latest victory. "I had to stick with it. [Sakkari] was throwing a lot at me and doing a lot of different things. So I had to try to counter that and use my aggressive game style as much as I could."

Collins will face No.4 seed Daria Kasatkina in Sunday's final. Kasatkina is one step away from her second Charleston title after edging past No.1 seed Jessica Pegula 6-4, 4-6, 7-6(5) in a gripping semifinal at the WTA 500 event.

Final countdown: Kasatkina leads Collins 2-1 in their head-to-head. Kasatkina won their only previous clay-court meeting at 2018 Rome. However, Collins won their most recent meeting, and that was in a final, when she notched a three-set win to claim the 2021 San Jose title.

"Danielle is, I think, playing the best tennis of her career right now," Kasatkina said after her semifinal victory. "She's fearless. When she feels her game, she's one of the most dangerous players on tour, and she definitely feels it right now."

Collins in the zone: With her first WTA 1000 title coming exactly a week ago in Miami, Collins has not rested on her laurels despite the surface switch from hard court to clay. The World No.22 picked up her 21st win of the year on Saturday, tied for third-best on tour behind only Iga Swiatek and Elena Rybakina.

"You have to be very versatile and flexible," Collins said about the change in surface. "I came into this tournament knowing it wasn't going to be perfect; the entire week there would be little bumps on the road and adjustments that would need to be made in the match, and sometimes that can be hard to do, but I've been flexible this whole tournament, with myself."

In the midst of her final season, Collins' current 12-match winning streak ties her career-best streak from 2021, when she won consecutive titles at Palermo and San Jose (including the aforementioned win over Kasatkina) before finally losing to Jessica Pegula in the Montreal Round of 16.

With her latest triumph, Collins leveled her head-to-head with Sakkari at two wins apiece, and she sits one victory away from her second clay-court title after that Palermo crown three years ago.

On Saturday, Collins saw a 3-0 first-set lead slide back to 3-3, but she won five straight games from there to lead 6-3, 2-0. Collins found incredibly clutch serves to erase two break points in each of her next two service games en route to the 1-hour and 25-minute win.

Collins has now beaten three Top 10 players in the span of one week. Last Saturday, she defeated No.4 Elena Rybakina in the Miami final, then upset No.6 Ons Jabeur in the Charleston second round before ousting World No.7 Sakkari.

Kasatkina's Charleston experience pays off: Earlier on Saturday, Kasatkina needed a grueling 2 hours and 47 minutes to best top-seeded Pegula. Kasatkina moved into her third singles final of 2024, following runner-up showings at Adelaide and Abu Dhabi.

Kasatkina continues her solid success on the green clay of South Carolina. She made her Charleston debut in 2017, and promptly reached her first WTA singles final that year before defeating Jelena Ostapenko for her maiden title.

Kasatkina has never lost before the quarterfinals in her five Charleston appearances, and she now holds an 18-3 career win-loss record at the event after denying Pegula her first final appearance of this season.

"Coming back here every year, it just feels like the first time when I came here," Kasatkina said. "I remember two days ago coming to the warmup on the stadium. I felt exactly the same like walking on this court from seven years ago."

Pegula's magic ends: Pegula pulled off multiple narrow escapes this week, beating Amanda Anisimova in a third-set tiebreak in the second round, and saving four match points in another third-set tiebreak win over Victoria Azarenka in the quarterfinals. However, the American could not complete another final-set tiebreak victory against Kasatkina.

Pegula was 2-0 against Kasatkina (4-0 in sets) coming into Saturday's clash, including a clay-court win at 2021 Rome, but Kasatkina upended that head-to-head this time around. The match was so close that Pegula actually won four more total points than Kasatkina, 116-112.

From 4-2 down, Kasatkina reeled off four straight games to win the topsy-turvy first set. The second set was similarly back-and-forth: Pegula missed out on five set points at 5-3, but she broke Kasatkina in the next game to tie up the match.

The third set also swung like a pendulum. Pegula was up a break at 2-0 before Kasatkina briefly held a break lead at 4-3. Eventually, the pair returned to parity, and Pegula found herself in a third-set tiebreak for the third time this week.

In the decisive breaker, Kasatkina's heavy groundstrokes began to take over, and she reached double match point at 6-4. Pegula saved the first match point with an unreturned forehand, but Kasatkina clinched victory with a crosscourt forehand winner of her own.