Who is in Jessica Pegula's player's box at US Open 2025? All about the American's support system in New York

Jessica Pegula has played some of her best tennis at the ongoing US Open. She has reached the semifinals without dropping a set and will face World No. 1 Aryna Sabalenka, who beat the American in last year's final at Flushing Meadows.

In her first five matches, Pegula defeated Mayar Sherif, Anna Blinkova, Victoria Azarenka, Ann Li, and Barbora Krejcikova. This is her best result at this year's Majors, as she lost in the third round of the Australian Open and the fourth round of the French Open. The World No. 4 suffered an opening-round exit at Wimbledon.

However, not all has been doom and gloom for Jessica Pegula in 2025. She has won a title on all three surfaces: the ATX Open (hard), the Charleston Open (clay), and the Bad Homburg Open (grass).

Let's look at who Jessica Pegula has in her player's box at the 2025 US Open.

1) Coaches: Mark Knowles and Mark Merklein

Mark Knowles at the 2025 US Open

Mark Knowles and Mark Merklein started working with Pegula in early 2024. With the two former players in her corner, the 31-year-old won her third and latest WTA 1000 title at the 2024 Canadian Open and reached her maiden Grand Slam final in New York.

Both Knowles and Merklein are from the Bahamas and excelled in the doubles category back in the day. Knowles is a former doubles World No. 1 and a three-time Grand Slam winner. Before Pegula, he coached Milos Raonic, Jack Sock, and Mardy Fish.

At the 2020 Olympics, Knowles partnered with Merklein, who achieved a career-high doubles ranking of No. 37.

Soon after Jessica Pegula roped in the duo last year, she said (via TNT Sports):

"I’m working in a combination with Mark Merklein and Mark Knowles. I like having a collaborative setup where I feel like I can talk to multiple people and have different feedback, and keep things fresh and motivating at the same time. We will see how it goes, but really excited.”

Pegula ended her five-year partnership with American coach David Witt after her second-round loss at the 2024 Australian Open. She achieved her career-best singles ranking of No. 3 under Witt's tutelage, for which he was declared the 2022 WTA Coach of the Year.

When they started working together in 2019, Pegula had been on the tour for a while, but her first WTA singles title came with Witt, who had previously coached Venus Williams.

2) Family

Jessica Pegula's husband, Taylor Gahagen, is a constant presence in tournaments in which she plays. A Williamsville, New York, native, Gahagen studied Business Administration at SUNY Fredonia and graduated in 2011. He did his MBA at Canisius College.

Gahagen, who stays low profile and avoids cameras, used to work at now-defunct Pegula Sports and Entertainment. He is now a Managing Partner at Dragos Capital and Agarwood Wealth.

Pegula and Gahagen had planned on tying the knot in October 2020. However, it was delayed due to the COVID-19 pandemic. They got married at the Biltmore Estate in North Carolina in 2021.

Jessica Pegula's brother Matthew is her youngest sibling, who often supports her from her player's box. He is accompanied by their sister Kelly, who famously saved their mother's life in June 2022. Kim Pegula suffered a cardiac arrest in her sleep and was unresponsive when Kelly performed CPR on her until an ambulance arrived.

In her column for The Players’ Tribune in 2023, Jessica wrote:

“Even though she doesn’t like to take credit for this terrible situation, she absolutely saved her life."

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Jessica Pegula wants "revenge" against Aryna Sabalenka in 2025 US Open SF

Aryna Sabalenka and Jessica Pegula

Jessica Pegula and Aryna Sabalenka's US Open semifinal on Thursday, September 4, will be their 10th tour-level meeting. The Belarusian is leading the head-to-head 7-2.

Neither of them has lost a set in the ongoing tournament in New York. Sabalenka reached the last four after Marketa Vondrousova withdrew ahead of their quarterfinal match due to a knee injury.

Jessica Pegula reached her maiden Grand Slam final at last year's US Open, where she lost to Sabalenka 7-5, 7-5.

Speaking at a press conference after confirming her semifinal against the World No. 1, the American said she was looking for "revenge."

"It would be cool to be able to get revenge, obviously. It’s going to be a tough challenge. But at the end of a Slam, you expect that to happen, and you expect people to be playing their best tennis and to be playing the best players, because those are the players that are playing the best," she said (via Yahoo Sports).

Sabalenka would be eager to defend her title, which would be her first Major this year. She lost in the finals of the Australian Open and the French Open, while getting knocked out in the semifinals at Wimbledon.