By Simon Evans

MASON, Ohio (Reuters) - Venus Williams showed that, almost a year after her health scare, she has the stamina needed as she battled for two hours 23 minutes to beat Russia's Maria Kirilenko 6-3 6-7 6-2 at the Cincinnati Open on Tuesday.

Williams served for the match twice in the second set, when up 5-4 and 6-5, but Kirilenko, the number 12 seed, fought well to push the first-round contest into a third set.

The American was on top throughout the third set, though, showing no signs of the physical ailments which cut short her campaign in the U.S. Open last year.

The seven-times grand slam singles champion winner pulled out of last year's U.S. Open citing an auto-immune disease, Sjogren's Syndrome, which causes fatigue and joint pain.

"I'm doing a lot better than this time last year," Williams told reporters. "So much better. So much better than a couple months of ago as well. I also am learning to deal with everything a lot better.

"If I wake up and I don't feel great, then I would panic and lose my match 2‑1. I had a few 2‑1s this year, too, but I had to take those losses in order learn and get better.

"Now I realize that I just kind of hang in there if I'm not having the best day and still try to get the win."

Williams had to skip the Australian Open in January and her comeback did not begin in earnest until she reached the quarter-finals at Miami in March.

Not that Williams is out of the woods yet - she continues to work with her medical team to reduce the impact of the disease.

"I'm trying different things all the time," she said. "Nothing can prevent bad days, but the bad days aren't as bad as they used to be.

"It's a work in progress. My main goal is to be 100 percent, but it's not like it goes away. It's still in my body trying to fight against me, but I'm fighting it as well."

Slovakia's Daniela Hantuchova fought back in the second set, surviving match point, to beat China's Zheng Jie 2-6 7-6 6-3 and she will next face Italian Sara Errani.

(Reporting by Simon Evans; Editing by Mark Lamport-Stokes)