In the latter half of the year, Clijsters entered only four tournaments. During the US Open Series, she won the Cincinnati Open, the tournament where she returned from retirement a year earlier. At her next event, she was eliminated in the quarterfinals of the Canadian Open by Zvonareva while struggling with a thigh injury. Nonetheless, Clijsters recovered to defend her title at the US Open. In the last three rounds, she defeated three top ten players in No. 6 Samantha Stosur, No. 4 Venus Williams, and No. 8 Vera Zvonareva. Venus came the closest to ending her title defense, but lost in three sets after serving two double faults in the second set tiebreak which could have won her the match. Clijsters won the final over Zvonareva with ease in less than an hour. This was her third consecutive title at the US Open and the fourth consecutive time she made it to the championship match, having skipped the tournament four times since 2003. Clijsters' final event of the season was the WTA Tour Championships, where she qualified for the seventh time. Despite a loss to Zvonareva in her last round robin match, she advanced to the knockout rounds and defeated No. 5 Stosur and world No. 1 Caroline Wozniacki for her third title at the year-end championships. Clijsters finished the season at No. 3 and was named WTA Player of the Year for the second time.