Indian Wells and Miami is one of the most difficult back-to-backs in tennis for myriad reasons. And yet, four intrepid and resourceful players found a way to advance to the quarterfinals in both events.

Elena Rybakina and Aryna Sabalenka ran all the way to the finals at the BNP Paribas Open, and they’re still on course for a possible rematch in the final at the Miami Open. Petra Kvitova, looking like the two-time Wimbledon champion she is, likes these fast courts. And Sorana Cirstea, ranked No.74 among Hologic WTA Tour players, continues to surprise.

"I think it's never happened to me, playing quarterfinals in Indian Wells and then quarters in Miami," Kvitova said. "So I have to see it very positively."

Three of these trending athletes are in play Wednesday in two quarterfinal matches from the bottom half of the draw:

No.2 Aryna Sabalenka vs. Sorana Cirstea

Sabalenka's off-the-charts athleticism is now guided by a calmer, cooler outlook. And the result is … a forceful fourth-round 6-3, 6-2 victory over Barbora Krejcikova. Two of their recent matches went the three-set distance, but when rain delayed the start of their Monday-nighter, Sabalenka knew what she needed to do.

“I don’t want to think about playing three sets that late,” she said afterward. “I was trying to stay focused and kind of relaxed. Don’t think too much about the time.”

It was over in 66 minutes, and Sabalenka is now 20-2 for the year, the best mark on the WTA Tour. Suddenly, the No.1 ranking seems a lot closer. Sabalenka left Indian Wells trailing Iga Swiatek by 3,235 points but when the defending Miami champion withdrew with a rib injury 1,000 points came off her total. Sabalenka is currently 2,030 points behind but can significantly reduce that margin with a few more wins here.

No.2 Sabalenka powers through Krejcikova to make Miami quarterfinals

Again, Sabalenka served superbly. She has gone unbroken in her last two matches and faced only a single break point against Krejcikova. She won 87 percent of her first-serve points -- the sixth time she’s surpassed 80 percent in 11 WTA 1000 matches this year. She’s hit 272 winners in those contests

Cirstea, a 7-6 (3), 6-4 winner over Marketa Vondrousova, is the only unseeded player remaining, but her ranking could vault into the Top 50 after results of the past several weeks. The 32-year-old Romanian has yet to drop a set in Miami and has beaten three quality players, including No.5 Caroline Garcia in the second round.

“I know it’s going to be very tough,” Cirstea said. “But I’ve been winning a lot of matches this American swing and I have the confidence. I know what I can play.”

Sabalenka has now played five events this year and reached the quarters in every one. This is her 15th WTA 1000 quarterfinal, tying her with Karolina Pliskova for the most since 2018. Sabalenka has never played Cirstea at this level but has an idea of what to expect.

“I got the chance to practice with her preseason in Dubai,” Sabalenka said. “She’s playing really great tennis, serving well. Playing great against top players. Yeah, really looking forward to this match.”

No.15 Petra Kvitova vs. No.18 Ekaterina Alexandrova

Kvitova is 33 now, but those heavy groundstrokes are still filthy fresh.

She is into her fourth quarterfinal at the Miami Open. The rest of the elite eight field has the same total (Sabalenka and Pegula with two each). This is Kvitova’s 35th quarterfinal at a WTA 1000, trailing only Agnieszka Radwanska (42), Simona Halep (39) and Caroline Wozniacki (36).

Miami: Kvitova powers past Gracheva into quarterfinals

Kvitova had to save five break points in the opening set but was a 7-5, 7-6 (5) winner over qualifier Varvara Gracheva. It was an energy-sapping win for the Czech, who was very pleased to get a day off before playing the quarterfinals.

"My legs were just down, they were starting to shake a little bit," Kvitova said. "I will see tomorrow how my legs are feeling. It's definitely not an injury."

Meanwhile, Alexandrova was leading Bianca Andreescu 7-6 (0), 2-0 when the Canadian retired with a left ankle injury. She left the court in a wheelchair. Previously, Andreescu had cleared out this section of the draw with impressive wins against Emma Raducanu, No.7 seed Maria Sakkari and Sofia Kenin.

Alexandrova, who entered the tournament with a 4-5 record, upset No.9 Belinda Bencic in the third round.

"Ekaterina is an aggressive player," Kvitova said. "She beat Belinda, playing good tennis. When she's on, she's just on. It's really difficult when she's serving well also. She's going for it no matter what."

Kvitova won their only previous match in the third round of the 2020 Australian Open 6-1, 6-2. In her 13th Miami appearance, she has an opportunity to reach her first semifinal.