Zvonareva falls to China's Li after long absence
Li Na serves to the Czech Republic's Petra Kvitova during their WTA Championships semi-final match in Istanbul on October 26, 2013
The 31-year-old Li, Asia's highest-ranked player in tennis history, beat Zvonareva 7-5 6-3 in one hour and 46 minutes.
It was the first singles event for Zvonareva since the 2012 London Olympics, after which the 29-year-old two-time Grand Slam champion was sidelined due to illness and a shoulder injury.
Zvonareva had triumphed over Li in four of their last five meetings, the most recent of which came in 2010.
Taiwan's Chan Yung-Jan, meanwhile, won a surprise victory over sixth-seed Zhang Shuai of China. Zhang took the first set 6-3, but Chan turned up the heat and battled back to win the next two, 6-4 and 6-2.
The year 2013 marks the second year for the Shenzhen Open, which comes as Li's success has ignited a new Chinese interest in tennis.