SAN JOSE, Calif. -- No.4 seed Daria Kasatkina will face No.7 Danielle Collins in the final of the Mubadala Silicon Valley Classic. Ranked No.31 and No.37, respectively, Kasatkina and Collins are enjoying a career resurgence after taking a time-out to address their mental and physical health.

Semifinal Report: Kasatkina oust top-seed Mertens, Collins breezes past Konjuh to set San Jose final

For Kasatkina, turning her prodigious career around meant delving into her psyche with a mental coach. After a stellar 2018 season that saw her make back-to-back quarterfinals at Roland Garros and Wimbledon, make the finals in Dubai and Indian Wells, win Moscow, and finish inside the Top 10, Kasatkina's results plummeted. She started the 2019 season ranked No.10. She finished ranked No.69 and would go into the 2021 season ranked No.71. 

"I was expecting too much from myself and that was obviously too much to handle," Kasatkina told reporters after her straight-set win over Elise Mertens in the semifinals. "At one moment I had a mental breakdown for a few months. 

"It's always difficult to come back because you're competing at the highest level. Just to come back you need twice more effort. That was tough. Actually, the pandemic helped me a little bit. There were no tournaments I had time to work on it."

"It's important to play against the opponent, not against yourself, the wind, or your coach. It's important to play against one person and not ten things that are not important."

- Daria Kasatkina

On the recommendation of her brother, Kasatkina began working with a mental coach at the end of 2019. With the tour shut down for much of 2020, Kasatkina met with her mental coach three times a week to get to the bottom of things. She emerged with a healthier perspective on her career, determined to never let her sense of self-worth be defined by on-court results. 

"When you work a lot, the hard work will pay off all the time," Kasatkina said. "I was just waiting for the moment when the puzzle would be completed."

"I feel completely different on the court. It's important to play against the opponent, not against yourself, the wind, or your coach. It's important to play against one person and not ten things that are not important."

Kasatkina's patience has paid off this season. On Sunday she will play in her fourth final of the season - two have been WTA 500 events - having already captured her first titles since that breakout 2018, winning the Phillip Island Trophy and the St. Petersburg Trophy. If she prevails on Sunday it will be the first time she has won three tournaments in a season. 

"When I was playing that final at Indian Wells (in 2018), I was in a different mental stage, Kasatkina said. "I was super happy and super excited playing in finals. Now I'm a bit more calm. I feel different. I know that I'm going to play a final tomorrow but I don't feel much different between the first round and today. 

"This is also the improvement I made. I don't spend a lot of mental energy right now."

"So to be able to wake up and say, 'Ok I can do this', and not have a doubt in my mind that I'm going to feel terrible, I just feel so lucky, honestly."

- Danielle Collins

Collins can relate. But whereas the spark that reinvigorated Kasatkina's career was mental, Collins' turnaround has been rooted in her physical health. Like Kasatkina, Collins' breakthrough season came in 2018. She started that season ranked No.162 and quickly emerged as one of the most dangerous floaters in any draw. Her breakout came with a Round of 16 at Indian Wells, followed by a semifinal at the Miami Open as a qualifier, and a semifinal showing in San Jose. She would finish the year inside the Top 40. 

But whereas Kasatkina's results went from feast to famine, Collins stayed in the Top 40 range while struggling to find week-to-week consistency. After struggling with debilitating pain throughout her career, the 27-year-old American was finally diagnosed with endometriosis earlier this year and underwent surgery in April. 

Since Wimbledon, she has now won 13 of her last 15 matches, including her first WTA title in Palermo last week. Collins, who has been traveling alone without a coach, credited the surgery for her recent success.

"Before having the surgery I was just not able to perform consistently tournament after tournament after tournament because I was constantly dealing with the many issues in that area," Collins told reporters after her dominant win over Ana Konjuh in the semifinals. 

"Now it's just given me so much confidence that my body is going to be able to show up consistently and I'm not going to be in physical agony or have to pull out of matches because of that issue. For me, it's so rewarding to feel like I'm healthy and this is the best I've felt in a long, long time."

Champion's Reel: How Danielle Collins won Palermo 2021

Now that she can rely on her body, Collins has been able to just focus on her tennis. This week in San Jose, she has defeated Shelby Rogers, Sloane Stephens, Elena Rybakina, and Konjuh to make the biggest final of her career. She has lost just one set over her nine-match winning streak. 

"It means the world to me because this is my career and this is what I love doing," Collins said. "This is what I've been doing since I was seven years old and I've worked so hard at it every single day. For so long, the frustration with what I was dealing with, with what I was going through, it was at times very sad because I felt I couldn't get my body to do what I wanted to do. 

"So to be able to wake up and say, 'Ok I can do this', and not have a doubt in my mind that I'm going to feel terrible, I just feel so lucky, honestly. For a while I just thought it was something I was going to have to deal with for the rest of my life."

On Sunday she will try to score her first win over Kasatkina - the Russian has won their two prior meetings - and become the only American to win a WTA 500 (or higher) tournament so far this season.  

"Whether I win or lose, I think I can walk away really happy with how I performed over the last couple of weeks and the progress that I've made to physically be consistent day after day," Collins said. "That's what I'm most proud of."

Kasatkina cruises past Mertens into San Jose final: Highlights