Caroline Wozniacki crushed Elena Dementieva 6-1, 6-1 at the WTA Championships in Doha on Tuesday to serve up a timely reminder to critics of her world No. 1 ranking.

Wozniacki blasted away from the baseline while Russian Dementieva could offer little in return, the Dane wrapping up the Maroon Group opener in 53 minutes at the Khalifa Tennis Complex in Qatar's capital.

In the White Group, world No. 2 Vera Zvonareva powered past a lethargic Jelena Jankovic 6-3, 6-0 to keep alive her slender hopes of grabbing the year-end No. 1 spot from Wozniacki.

In the day's last match, Australian Sam Stosur beat Francesca Schiavone to gain a measure of revenge for her defeat in the French Open final in June.

Italy's Schiavone had raced to a 4-0 lead in the first set but Stosur battled back to win 6-4, 6-4.

"A very nice start, definitely," Wozniacki said after brushing aside Dementieva.

"I'm very happy to be through this first match. It's always tough to start a new tournament. Against Elena, we have had so many tough matches in the past. It's nice to get this one."

Wozniacki has come under fire after reaching the pinnacle of women's tennis without winning a grand slam, and the absence of No. 3 Serena Williams from the prestigious US$4.55 million tournament has done little to quieten the critics.

But the 20-year-old looked every inch the world's top player on Tuesday, picking off the Russian's curious windmill-style serves and dominating her own service games with a relentless mix of pressure and power.

Wozniacki whizzed through the first set, Dementieva bewildered by the Dane's shot-making skills and her own inability to keep the ball in play.

The second set proved just as painful for the Russian, who is making her 10th appearance at the WTA Championships.

Wozniacki painted the lines with pinpoint passing shots and pressed the power button when Dementieva tried to trade blows from the baseline.

The Russian admitted her gameplan of bringing Wozniacki to the net with drop shots had backfired.

"I think I wanted to take her from the comfort zone. She's feeling very solid at the baseline," said the 29-year-old Dementieva.

"For sure it was not a very good selection of shots to do it every single point. I just feel like I was not focused on the game today."

Verve and zip

Earlier, Russian Zvonareva, decked out in host Qatar's colors of maroon and white, had much more verve and zip than her struggling Serbian opponent, who offered only fleeting resistance before capitulating in the second set to lose 3-6, 0-6.

Jankovic had exited her two previous tournaments in the second round citing ill health and was clearly under the weather.

"I think it's very difficult for most of the players to show their best tennis in the first match," Zvonareva said.

"Maybe I didn't show my best tennis today. I had a few unforced errors in that first set, but I think overall I played really well.

"I think it was very good performance from me and it just feels an amazing to win my first match at the Championships."