NEW YORK - Tennis fans at this year's U.S Open can now watch the world's top players battle it out in 3D cartoon form while chatting with an AI commentator that has been trained to bite its digital tongue when things get heated.

The tournament has introduced technology that transforms real matches into animated replays featuring robot-like doppelgangers of tennis stars, complete with a chatbot that offers insights but diplomatically dodges drama. 

When world number one Jannik Sinner stepped up to serve in his first round match, his AI version took more than a minute to materialise on phone screens, jumping out of thin air in yellow attire, minus the white sleeve covering Sinner's injured arm.

The 3D feature uses player tracking data to recreate matches through cartoon-like figures on the official app, according to Tyler Sidell, Technical Program Director for IBM's Sports & Entertainment Partnerships. 

"If you want to go back and see where that ball landed and see the trajectory of the ball, it's a great tool for that," Sidell told Reuters. "It's also for people on the go. I might be on the train... coming to the U.S. Open, and I'm not able to stream."

Not everyone is serving up praise for the digital innovation. Sue Morgan, a retired U.S. Open visitor from Atlanta, Georgia, was less than impressed. "It's a little weird," she said. "I didn't love it, no. It's not real."

The app's Match Chat feature proved both psychic and diplomatically vague during Sinner's match against Czech player Vit Kopriva, correctly predicting a 92% likelihood of victory for the Italian. 

However, when asked about Sinner's performance, the chatbot hedged its bets, agreeing in separate messages that it could be considered both "great" and "slightly underwhelming."

The AI commentator has been programmed with a strict vocabulary filter using curse words from both American and British English, lessons learned from its deployment at Wimbledon earlier this year. 

When former champion Daniil Medvedev smashed his racket after losing on day one, the chatbot played diplomatic defence: "Thank you for your request. This data isn't available for this match at the moment."

With about 5 million chatbot interactions recorded so far, IBM's Sidell said the technology aims to complement rather than replace the live tennis experience, though some fans clearly prefer their Grand Slam action served up the traditional way. REUTERS