Emma Raducanu and her new coach, Francisco Roig, landed themselves in hot water as the Brit took on world No. 1 Aryna Sabalenka at the Cincinnati Open. Roig, who previously spent years working with Rafael Nadal, joined Raducanu's coaching camp this week following a successful post-Wimbledon trial.

And the Spanish tennis coach made his voice heard throughout the first set, shouting words of advice and encouragement. However, they took things too far when Raducanu survived a tough service game to lead 5-4 and walked over to chat to Roig, before the umpire told her she wasn't allowed to approach her mentor.

Neither Raducanu nor Sabalenka wanted to go down without a fight in a rematch of their tight Wimbledon third-round scrap, which saw Sabalenka come from a break down in both sets to win 7-6 6-4.

They traded breaks twice early on, and the Brit found herself in a tight spot at 4-4, saving two break points. Roig made himself heard throughout the match, shouting out after virtually every point.

After Raducanu held on to lead 5-4, she walked to the corner to say something to Roig, who also left his seat and walked closer to communicate with his player. But the umpire quickly called her over.

“She’s even going over for some advice before heading to her chair. Huge amount of dialogue at the moment, and the umpire has just called her away, can’t do that,” Sky Sports commentator Adam Fielder remarked.

Raducanu sat at her bench and immediately wrapped an ice towel around her neck on what was a hot day in Cincinnati, with the heat rule in effect. The chair umpire quickly leaned over and reminded the 22-year-old that neither she nor her coach could approach each other.

“Emma, you cannot actively approach him and he cannot leave his position. You know that. You cannot have a conversation,” the official said.

“I can’t hear anything because the music is really loud,” Raducanu replied. But the umpire wasn’t having it.

She explained: “Then he needs to speak louder but you cannot actively approach him, he cannot leave the position, he needs to stay where he is and you cannot actively go towards him. You cannot actively go at the end of a game especially.”

The world No. 39 quickly apologised, adding: “Okay, sorry, I didn’t know that. Can you tell someone to tell him? I can’t say it like now.”

The umpire offered to send a referee over to speak to Roig, but told Raducanu it was fine for her to relay the message to her coach while she was at his end of the court.

At the end of the changeover, Fielder reminded viewers that it was against the rules for Raducanu and Roig to actively approach each other. “Very interesting that dialogue there between umpire, Raducanu, coach,” he said.

“So the coach is not allowed to get up off his or her seat to move closer to the player to interact with them, and the player cannot go over at the end of a game to have a conversation.”

The first set went to a tiebreak and, just like their match at Wimbledon, it was Sabalenka who won it to move ahead.

To be the first to receive the latest tennis news, join our WhatsApp community or newsletter