Serena Williams came into Cincinnati looking to keep her winning streak going - and she did, up to 19...
Meanwhile Jelena Jankovic, a finalist in Cincinnati in 2011, was edged in her opening match by Peng Shuai.
Sam Stosur fought through some tough moments to make the quarterfinals, where she fell to Venus Williams.
Angelique Kerber and Serena Williams with baseball star Joe Morgan, who played on the Cincinnati Reds.
Serena Williams' quarterfinal match with Angelique Kerber on Friday did not go the way she planned it...
Angelique Kerber never lost serve and converted on both of her break point chances to take the match, 64 64.
Serena Williams had won 36 of her last 37 matches, her only loss since April being the French Open loss.
Angelique Kerber rejoiced after beating Serena Williams and moving into the semifinals of the Premier event.
The first semifinal Saturday night saw Li Na take on Venus Williams. Li went into the match 2-0 against her.
And Li Na would improve to 3-0 against the former World No.1, taking a see-saw three-setter, 75 36 61.
Sunday's doubles final saw Andrea Hlavackova and Lucie Hradecka take on Katarina Srebotnik and Zheng Jie.
Andrea Hlavackova and Lucie Hradecka followed up their Wimbledon and Olympic finals with the Cincinnati title.
The singles final followed, with Li Na rallying from 61 31 down to make it past Angelique Kerber, 16 63 61.
Li Na captured her sixth WTA title, and first since her famous French Open victory all of 14 months ago.
Li Na's win didn't push her up from No.9 in the world, which will make her a dangerous No.9 seed in New York.