Serena Williams' ex-coach Rennae Stubbs issues harsh criticism of Nick Kyrgios' latest comments on Lleyton Hewitt's son over Jannik Sinner collab 

Serena Williams' ex-coach Rennae Stubbs slammed Nick Kyrgios for "embarrassing" Lleyton Hewitt's son Cruz online over collaboration with Jannik Sinner. While Kyrgios defended his remarks, calling them a "joke," Stubbs strongly disagreed with his justification.

Kyrgios left multiple controversial comments on Cruz's Instagram post showing off his practice session with World No. 1 Sinner. The 29-year-old, who has regularly criticized Sinner following his doping controversy, expressed his disappointment with Cruz.

Nick Kyrgios wrote:

"Love ya Cruz but this is wild 😢"

"Thought we were boys 💔💔💔💔💔💔💔💔💔"

"Cooked post 💉"

Nick Kyrgios' comments on Cruz Hewitt's post with Jannik Sinner | Instagram @cruzhewitt

The 2022 Wimbledon runner-up faced criticism for his comments but he defended himself claiming it was a "joke."

On a recent episode of her podcast, Stubbs, who coached the likes of Serena Willimas and Eugenie Bouchard, tore into Kyrgios for his comments. She mentioned how for Cruz Hewitt, receiving a qualifying wildcard for the Australian Open and practicing with defending champion Jannik Sinner was an invaluable opportunity to learn and improve.

"So what better preparation to play with a defending champion who is going to teach you so much about how to be a better tennis player on the court? Why wouldn't you hit with him? That is an opportunity that any kid would want," Rennae Stubbs said (at 25:50).

Stubbs emphasized that any aspiring player would jump at such a chance. She criticized Kyrgios for publicly ridiculing Cruz on social media, calling it inappropriate and embarrassing.

"To give the guy sh*t on social media and go after him. It's not a joke. If you want to joke about it, then you call his dad or you call him, because I'm pretty sure you have either of their numbers, and you give him sh*t. You don't give him sh*t on a public forum, that's embarrassing to him. He just doesn't know how to stop and learn to be an adult in these situations," she added.

---

Nick Kyrgios denies personal grudge against Jannik Sinner, slams Andy Roddick for entertaining speculation

Jannik Sinner at the 2025 Australian Open Previews - Source: Getty

Nick Kyrgios has been vocal in his criticism of Jannik Sinner since the no-fault ruling received by the Italian after testing positive for Clostebol.

Tennis journalist Jon Wertheim speculated on Andy Roddick's Served podcast that Kyrgios' animosity might not stem from genuine concerns about doping but from personal grievances. He suggested that Sinner’s relationship with Anna Kalinskaya—who briefly dated Kyrgios in 2020—could be a contributing factor.

"This is just a personal vendetta. There is a woman involved here, who also happens to be a player," Wertheim said.

"But he didn't even seem to understand the doping protocols and the context to begin with which leads me to conclude this is all just a bad faith vendetta against a player who's now dating a former girlfriend and nothing more," he added.

Kyrgios fiercely denied these claims. He also criticized Roddick, calling him a "sheep" for entertaining the journalist’s remarks.

"Hahaha of course - sweep sweep sweep, how is this now my fault? I couldn’t care less where sinner lays his wood 😭😂 I’m in a happy relationship 🙏🏽 I just don’t like people who are cheating the system. Roddick - never ever thought you were a sheep my guy lol," Nick Kyrgios posted on X.

In tennis terms, both Nick Kyrgios and Jannik Sinner are preparing for the Australian Open. The Aussie recently aroused injury concerns about his wrist and abdomen while the Italian is looking in good shape taking part in practices in Melbourne.