Williams had won nine of their 11 previous meetings, including six straight. And as she built a 62 31 lead it looked like the streak would be extended to seven; but Dementieva, the No.5 seed, fought back to take the second set and beat the No.7 seed, 36 76(6) 62. Highlights: V. Williams vs. Dementieva
"I was trying to fight for every point. I was trying to stay positive," Dementieva said after the match. "It was very important to come back and win the tie-break. I think she was a little disappointed in the beginning of the third set and gave me a little bit of an advantage, and I was able to finish the match." Interviews: Dementieva Rallies on Day 1
"She hung around. She really stayed in there. She did really well," Williams said. "I just didn't put enough balls in the court. It was pretty close in the second set and I had a lot of opportunities to have an even bigger lead than I did, but it doesn't help if you don't put the ball in the court. It was a tough loss." Highlights: Shot of the Day
Williams was also the defending champion in Doha, having taken the season-ending title a year ago. Thanks to the round robin format however, the 29-year-old still has a shot at winning; she plays her second match Wednesday. Highlights: Day 1
"I'm going to come back tomorrow and just improve my game," Williams added. "That's what it's all about in round robin tennis. It's my second time playing round robin. Now I'll see what it's like to be in this kind of competition for real."