LONDON (Reuters) - Former world number one Kim Clijsters began her final Wimbledon campaign in style on Monday, beating 18th seed Jelena Jankovic 6-2 6-4.

Belgian Clijsters, who has said she will retire for the second time in September, after the U.S. Open, looked to be back on form after an abdominal injury forced her to pull out of the Den Bosch tournament before her semi-final last week.

"It felt okay," she said of the injury on Monday, in a television interview. "I had a bad stomach-muscle injury in Toronto a year-and-a-half ago and I didn't want that to happen again so I think pulling out last week was a good choice."

The 29-year-old Clijsters, who came out of retirement in 2009 after having a baby and has won four grand slams, faces Czech Andrea Hlavackova in the second round.

(Reporting by Clare Fallon, editing by Pritha Sarkar)