We're down to the final four in Indian Wells. Victoria Azarenka, who has strung together some vintage tennis in the desert, takes on Jelena Ostapenko, while Ons Jabeur, coming off a win that will catapult her into the Top 10 come Monday, squares off against Paula Badosa.

Each player has a compelling reason she can walk out of the final WTA 1000 event of the year with a title. But it's not going to be easy. 

"In terms of game-wise, conditions are pretty tricky here," Azarenka said. "It's about adjustment a lot and navigating through two weeks. It's a two-week event, so it also takes a lot of energy a lot of focus out of you."

Between tricky conditions and even stiffer competition, how will this final four play out? We take a look at the keys for each of the remaining players.  

No.24 Jelena Ostapenko vs. No.27 Victoria Azarenka

Key for Ostapenko: Stay aggressive and keep up the first-serve percentage 

From week to week – and indeed match to match, if not game to game – Ostapenko's career has been a rollercoaster ride. But two things that have remained constant are her unwavering self-belief and her absolute commitment to all-out power tennis. The win over No.2 seed Iga Swiatek in the third round extended her streak of scoring at least one Top 10 victory every year since 2015, when she debuted at tour level (and took her overall total to 14). After that match, as well as the follow-up quarterfinal defeat of Shelby Rogers, Ostapenko stated the key to winning was that she had stayed aggressive – as though doing otherwise has ever occurred to her.

"If I play well, I'm a dangerous player and I can, I think, beat anyone," Jelena Ostapenko said after upsetting Swiatek. 

Watching the Latvian Ostapenko in full flow, it's hard not to agree with her. Big hitting is commonplace on the WTA Tour, but Ostapenko takes it to extremes. No angle is too impossible for her to attempt; no ball too awkward to take at full blast. Broadening her repertoire over the years to include the dropshot has simply expanded the ways in which she can boost her beloved winner tally. In combination with her charisma, this can make for electric entertainment.

And recently, it's also made for her most consistent run of results since 2017, the year she won Roland Garros. Ostapenko's run in Indian Wells has meant she has scored more than 30 WTA main-draw wins in one season for the first time since. In June, she collected her biggest title since her French Open fairytale in Eastbourne. And here, she's landed in her biggest semifinal since Wimbledon 2018.

Ostapenko lost her only previous meeting with Victoria Azarenka 6-4, 7-6(4) in the first round of Roland Garros 2019, but she's never been one to be deterred by a losing head-to-head. For all that Ostapenko can control the match off the ground, though, she will need to be careful of her serve. Though the double-faulting issues that have plagued her in the past seem to have been eradicated, her second serve remains a weakness that a renowned returner such as Azarenka can feast on.

But Ostapenko can negate that disadvantage with her own ferocious return, which she will happily blitz into the corners whenever possible. If that's clicking and she keeps her first-serve percentage high, Ostapenko should have a solid foundation to dominate baseline exchanges. -- Alex Macpherson

Key for Azarenka: Take care of her side of the court

Victoria Azarenka debuted as a professional at a $10,000 ITF event in Israel – she was 14 years old.

Eighteen years later, at the age of 32, she’s still swinging, still playing meaningful matches. And as she has showed at Indian Wells, impressive matches as well. 

The No.27-seeded Azarenka defeated Jessica Pegula 6-4, 6-2 and has yet to drop a set. Friday, she meets No.24 Jelena Ostapenko, who was a three-set winner over Shelby Rogers. Azarenka won their only meeting, in the first round of the 2019 French Open.

Her key? Efficiency. 

"I think the court coverage and taking maybe less shots to win the point, that's something that is important for me to improve," she said after the semifinals.  "I think on the baseline, counterattacking, having high intensity, that's something that worked really well for me. I'm looking for things that I can implement that will make it a bit easier for me." 

Azarenka has won 21 titles – two of them at Indian Wells, in 2012 and 2016. She loves the desert air; only three women have won more than her 32 matches here, and their names are Davenport, Sharapova and Wozniacki.

All she’s done this year at Indian Wells is take out fellow two-time major winner Petra Kvitova (6-2, 6-2), then cooled off the unseeded Aliaksandra Sasnovich, who had scored back-to-back upsets over US Open champion Emma Raducanu and Simona Halep.

Azarenka has always been a complete player, but this year she’s been trying to add a new wrinkle – aggressiveness. So far, it’s a work in progress, but this week it’s working.

In her post-match press conference, Azarenka was asked about Ostapenko’s aggressive play. Her answer underlined the wisdom Azarenka has accrued over her long career.

“I don’t necessarily think any differently,” Azarenka said. “It’s kind of the same mindset, taking care of your side of the court and not letting the other, your opponent, control the outcome. I think that doesn’t necessarily change my approach. It may change some rallies, some shots, but approach definitely not.” -- Greg Garber

No. 12 Ons Jabeur vs. No. 21 Paula Badosa

Key for Jabeur: No nerves, and slam back second serves

With a place in the Top 10 and a spot at the Akron WTA Finals in her sights, Ons Jabeur started Indian Wells under a bit of self-imposed pressure.

“I'm trying so hard to calm myself down and handle all this stress because I want to be a Grand Slam champion,” Jabeur said on Thursday. “If I want to do that, then I need to go through this. Hopefully I'll go through this without having a heart attack,” she said with a smile.

Jabeur can breathe easier because she will make her Top 10 debut in next week’s rankings. She is also up to No.8 in the Porsche Race to the WTA Finals, meaning a trip to Guadalajara is still a possibility.

Looking back on the past few months, the stress might have been unwarranted. Jabeur has gone deep in many events this summer, including a historic first title in Birmingham, a second Grand Slam quarterfinal at Wimbledon, and another final in Chicago. She’s won 19 of her past 25 matches.

Any doubts about Jabeur’s nerves in the past have been fully obliterated. “Finally, with maturity and enough experience, I’m accepting this kind of pressure is a privilege, it's a pleasure to have it,” she said.

It certainly helps alleviate the pressure when your form is at its peak. After a tough opening match against fellow crafty player Anastasija Sevastova here in the desert, Jabeur won her next three matches in straight sets.

Jabeur has been helped by solid second serves and second-serve returns. In her past three matches, she has won over half of the points returning her opponent’s second delivery (including 71 percent against Danielle Collins), while also never ceding more than 40 percent of her own second-service points.

That should come in handy against Paula Badosa in the semifinals. The Spaniard’s powerful game is not to be trifled with, but Badosa won only 47 percent of her second-service points combined in her straight-sets wins over major champions Barbora Krejcikova and Angelique Kerber in the past two rounds. Jabeur should continue to attack those second serves.

But win or lose, Jabeur is primed for an incredibly high year-end finish in the rankings and a run at the Grand Slam title she desires in 2022. Why be stressed? -- Jason Juzwiak

Key for Badosa: Let's get physical

Paula Badosa became the first Spanish woman since 2003 to advance to the semifinals in Indian Wells after scoring back-to-back wins over major champs. The 23-year-old Spaniard started her desert campaign with a straight-sets win over Coco Gauff and is into Friday's semifinals with victories over Barbora Krejcikova and Angelique Kerber. She did not drop a set against those three opponents. 

Match Report: Badosa bests Kerber to make Indian Wells semis; faces Jabeur

In short, Paula Badosa has looked sharp in her Indian Wells debut. And if history is any indicator, she is going to cause fits for Jabeur. 

As Gauff, Krejcikova, Kerber and Dayana Yastremska have found over this fortnight, hitting through Badosa is a tough task. After splitting with coach Javier Marti before the US Open and linking up with childhood coach Jorge Garcia, Badosa has played tactically sound tennis all week to make her first semifinal since winning her first title in Belgrade. Though she is nursing a shoulder injury that derailed her summer season, Badosa played physical, smart tennis to minimize her errors while keeping the baseline pressure on her opponents.

The result has been 20 breaks of serve over four matches. She dropped just one set all tournament and Badosa broke Krejcikova six times, Kerber and Yastremska five times each and Gauff four times. By comparison, Badosa has been broken just nine times. 

Badosa and Jabeur have played twice on tour, both on hard courts, and both times it came down to the wire. Badosa won their first meeting at the 2015 US Open, winning 7-6, 2-6, 6-4 in the first round of qualifying. Jabeur narrowly won out earlier this year in Miami, winning 7-6, 5-7, 7-5 in over two-and-a-half hours.

The key for Badosa will be to keep the rallies physical and shrink the court on Jabeur. Breaking down the Jabeur game requires an effective backhand down the line, and Badosa has never been shy about pulling the trigger on that rally-breaking shot. -- Courtney Nguyen