Former world number one Kim Clijsters has been out of action since August with a stomach injury.

Story highlights

Kim Clijsters beats world No.1 Caroline Wozniacki on her return from injury

Four-time grand slam winner Clijsters scored a 6-2 7-6 (7-5) success

The pair faced each other in an exhibition match in Antwerp, Belgium on Thursday

Sweden's Robin Soderling will miss January's Australian Open due to long-term illness

CNN  — 

Four-time grand slam champion Kim Clijsters made a successful return from injury by defeating world number one Caroline Wozniacki in an exhibition match in Antwerp, Belgium.

Clijsters, U.S. Open champion in 2005, 2009 and 2010, has been out for almost four months after sustaining a stomach muscle injury in August.

“So far, and today, everything felt really great,” the 28-year-old said told the 10,000-strong crowd after winning 6-2 7-6 (7-5) at the Antwerp Sports Palace on Thursday.

The Belgian will now focus on preparing to defend her Australian Open crown in Melbourne in January after securing victory in one hour and 35 minutes.

Clijsters climbed to the top of the world rankings in February before sustaining shoulder and ankle injuries in April. She injured her stomach while attempting to recover in time to challenge for a fourth U.S. Open title and is only now regaining full fitness.

“I am happy to have played a match and break the rhythm of daily training,” the 41-time WTA Tour winner said.

Clijsters initially retired from tennis in 2007 to concentrate on raising her daughter, but in 2009 she performed a u-turn and announced she would return to sport.

It was a spectacular comeback as Clijsters gained wild-card entry to the U.S. Open before going on to win the title at Flushing Meadows two years in a row.

However, the Australian Open draw will be missing Sweden’s former world No. 4 Robin Soderling, who has confirmed his absence from the 2012 season’s first grand slam.

The two-time French Open finalist contracted the virus infectious mononucleosis in September, but his recovery has taken longer than initially anticipated.

“I am feeling better with each day but it will still take some time before I can start practicing in full speed,” the 27-year-old said via his official Twitter account.

“My goal is to start with practice in January and I hope for tournament comeback in February, but at this stage it is hard to know when and where.

“I hope my body will allow me to do that. I will try to give you more updates. I love reading your messages and appreciate your support and encouragement very much.”

Soderling has not played since defeating David Ferrer to win the Swedish Open on home soil in July, but still finished the year ranked 13th.