RIYADH, Nov 2 (Reuters) - Aryna Sabalenka began her quest to secure the year-end number one ranking with a thumping 6-3 6-4 victory over China's Zheng Qinwen in her opening round robin match at the WTA Finals in Riyadh on Saturday.

Australian and U.S. Open champion Sabalenka, who is headlining the first women's professional tennis tournament in Saudi Arabia, packed far too much power for Zheng at crucial points in their fourth meeting of 2024 to stay perfect.

In a rematch of their Melbourne and Wuhan title clashes, it was Belarusian Sabalenka who edged ahead in a tight opening set with a break in the sixth game and took the early lead in the contest by holding to love.

Olympic champion Zheng enjoyed plenty of vociferous support at the King Saud University Indoor Arena and led four times in a closer second set but Sabalenka drew level each time and finally broke for a 5-4 lead with a searing forehand winner.

She wrapped up the contest on serve despite a wobble with a double fault, when Zheng sent a forehand long.

The WTA Finals, which features the top eight singles players and doubles teams in the world and has a record prize pot of $15 million, will culminate with the title clashes on Nov. 9.

Winning three round robin matches or reaching the final are some of the ways Sabalenka can retain top spot this year, while closest challenger Iga Swiatek needs to successfully defend the trophy to have any chance of overtaking her.

Roland Garros and Wimbledon runner-up Jasmine Paolini plays 2022 All England Club champion Elena Rybakina in the second contest from the Purple Group later.

Swiatek takes on Barbora Krejcikova in the Orange Group on Sunday before Coco Gauff meets Jessica Pegula.

(Reporting by Shrivathsa Sridhar in Bengaluru, editing by Pritha Sarkar)

((Shrivathsa.Sridhar@thomsonreuters.com;))