of the USA holds three of the four grand slams titles while Safina is yet to win a grand slam.
Serena Williams last year won the US Open before this year taking grand slam titles at the Australian Open and Wimbledon.
The 23 year old Safina after losing in the Wimbledon semifinals to the third ranked Venus Williams of the USA 6-1, 6-0 took her third title of the year at the Banka Koper Slovenia Open last month.
Safina, seeded number one at this week's LA Women's Tennis Championships, could not have faced the Williams sisters in Los Angeles as neither sister was entered.
Safina could have met the unseeded and fellow Russian Maria Sharapova in the final. Sharapova topped the WTA tour rankings last year before undergoing a shoulder surgery which left her sidelined for several months.
In tonight's third round match, the two players split the first two sets before Safina broke serve to go ahead 4-2 in the decisive third set. However with the contest approaching the two hour mark, Zheng took the next two games to level the set at 4 all.
Then the 26 year old Zheng broke Safina's serve at love to lead 5-4 before holding serve at love for the stunning upset after two hours and ten minutes.
Safina going into the match had led Zheng head to head 4-0, but had struggled in Rome in the spring in the round of sixteen, defeating Zheng 5-7, 6-1, 7-6(7-3) in route to taking the Rome title which would originally push her to the top women's ranking.