“This change is really challenging for me, and this decision wasn’t easy, either,” Iga Swiatek wrote in 2021 as she announced her split from longtime coach Piotr Sierzputowski, the same man who had guided her from juniors to senior tennis. Yet when they parted ways, Swiatek mentioned the need for change to evolve. But now, Sierzputowski has finally spoken out about the real reason behind their separation.

Just recently, Sierzputowski spoke to Sport.pl and finally put words to what had gone unsaid for years. “I’m proud of how we worked together. But something fizzled out, and it was time for a change. It was Iga’s decision, not mine, but, honestly, I felt a kind of relief because we both felt that this was the right time.”

They began their collaboration all the way back in 2016, when Swiatek was a fourteen-year-old on the junior circuit. Under Sierzputowski, not only did Swiatek improve, but she also became a worldwide tennis sensation. The greatest successes were their 2018 triumph at Junior Wimbledon and the ensuing surprise victory at the French Open in 2020.

By the end of 2021, Swiatek had established herself among the world’s top players. But the coach described their relationship as an intense professional journey that naturally reached its limit.

“Something simply ended,” he said. “We started together, we rose to the top together. I am very happy with what we did… But something burned out, and it was time for a change. It happens in every job, especially in dynamic sports.” But Iga Swiatek, too, handled the split with grace.

In her farewell message at the time, she said, “I thank Coach for everything he’s done for me. We’ve given each other so much, and I hope that with this shared value and experience, we’ll continue to grow and find professional fulfillment. Coach, I owe Coach a lot, and I’m so grateful for the time we’ve shared together, which has led us to where we are now.” Still, after five demanding years, she felt it was time for a reset and a new challenge.

That change soon reshaped her career in dramatic fashion. Shortly after ending her partnership with Sierzputowski, Iga Swiatek began working with Tomasz Wiktorowski. What followed was one of the most dominant seasons in modern women’s tennis. In 2022, she compiled a 37-match winning streak and several titles, including Roland Garros and the US Open, and she won the world number one ranking with authority.

As for Sierzputowski, he shifted his focus to other players under his tutelage.

Iga Swiatek’s former coach sets sights on developing Murphy Cassone

Since parting ways with Swiatek, Piotr Sierzputowski has coached Hungary’s Dalma Galfi, American Shelby Rogers, and also an upcoming star, Tomasz Berkieta. In the spring, the 33-year-old took on a fresh challenge, coaching the 23-year-old American Murphy Cassone.

Cassone’s rise has not followed a smooth path. For years, he juggled competitive tennis with life as a student at Arizona State University, where strict academic rules limited how often he could compete on the ATP Tour. Everything changed in the fall of 2024 when he captured the Challenger title in Calgary. That breakthrough win convinced him that he truly belonged on the professional stage.

Their partnership came together almost by chance in early 2025. “It was quite funny,” Sierzputowski recalled. “The day I broke up with Dalma, Murphy sent a message asking if we could talk. We quickly decided it was worth trying to work together.” The goals were ambitious from the start. Sierzputowski made it clear that the target was to push Cassone into the ATP Top 150 this year and into the main draws of Grand Slam tournaments next season.

In a fascinating twist, Cassone even found himself sharing the court with Iga Swiatek in Paris, training alongside the four-time champion in a session. And the progress soon followed. Before the US Open qualifiers in August, Cassone had climbed to No. 172 in the ATP rankings. Although a few difficult weeks later in the season saw him finish the year at 216, the upward momentum of his journey under Sierzputowski is clearly just beginning.