Daria Gavrilova of Russia hits a return to Serena Williams of the United States during the women's singles first round match at the WTA Qatar Open tennis tournament in Doha, Qatar, Feb. 12, 2013. Williams won 2-0. (Xinhua/Chen Shaojin)

Serena Williams of the United States hits a return to Daria Gavrilova of Russia during the women's singles first round match at the WTA Qatar Open tennis tournament in Doha, Qatar, Feb. 12, 2013. Williams won 2-0. (Xinhua/Chen Shaojin)

Serena Williams of the United States celebrates scoring during the women's singles first round match against Daria Gavrilova of Russia at the WTA Qatar Open tennis tournament in Doha, Qatar, Feb. 12, 2013. Williams won 2-0. (Xinhua/Chen Shaojin)

Daria Gavrilova of Russia hits a return to Serena Williams of the United States during the women's singles first round match at the WTA Qatar Open tennis tournament in Doha, Qatar, Feb. 12, 2013. Williams won 2-0. (Xinhua/Chen Shaojin)

Daria Gavrilova of Russia reacts during the women's singles first round match against Serena Williams of the United States at the WTA Qatar Open tennis tournament in Doha, Qatar, Feb. 12, 2013. Gavrilova lost the match 0-2. (Xinhua/Chen Shaojin)