Kenin 'nervous' ahead of Australian Open defence

Sofia Kenin admitted Tuesday she was "very nervous" ahead of her Australian Open title defence, but returning to the site of her breakout triumph had rekindled special memories.

The world number four's much-awaited return to Melbourne Park was brief after her opponent Camila Giorgi retired with a thigh injury after one set at the Yarra Valley Classic.

Kenin clinched a tight first set 7-5 but was hoping for more court action having lost in the quarter-finals of last month's season-opening WTA event in Abu Dhabi when top seed.

The 22-year-old was back at the scene of her stunning breakthrough Grand Slam title last year, where she beat Garbine Muguruza in three sets.

Kenin said the prospect of defending a major will be a new challenge when the Australian Open starts on February 8.

"Obviously very nervous. It's the first time I'm experiencing coming back to a Grand Slam where I want to try to defend my title," she said.

"Of course, there's nerves, but I'm going to do my best and we're going to see how it goes."

The American emerged as a serious force in last year's truncated circuit, continuing her momentum from Melbourne by reaching the French Open final and rising to a career-high four in the world rankings.

"I feel like with the matches I've had, the success I had last year, helps me," she said.

"I feel like it's going to be a little bit of a rollercoaster next Monday or Tuesday, whenever I play. I feel like the fans will see a little bit more emotion."

Having emerged from a mandatory 14-day quarantine, where she was allowed to practise five hours a day with former French Open champion Jelena Ostapenko, Moscow-born Kenin said she was excited about being back in Melbourne.

"It's really special. Super glad to be here," she said. "I'm trying to somehow handle the emotions on court.

"I'm happy with the win, the way I played ... just made a little bit too many unforced errors."

She faces Germany's Mona Barthel or Jessica Pegula of the United States next.