London, England (SportsNetwork.com) - Reigning two-time champion Novak Djokovic was an easy winner Monday in round-robin action at the season-ending ATP World Tour Finals.
The world No. 1 star dismantled eighth-seeded U.S. Open champ Marin Cilic 6-1, 6-1 in a mere 56 minutes at The O2. Djokovic piled up six breaks of serve, compared to only one for the overmatched Cilic.
The three-time Tour Finals titlist Djokovic topped Rafael Nadal in last year's finale in London. Nadal is not playing this year after undergoing surgery to remove his appendix, which opened the door for Cilic to qualify for this exclusive eight-player event.
Djokovic (1-0) heads up this week's four-player Group A, which also features Stan Wawrinka (1-0), Tomas Berdych (0-1) and Cilic (0-1).
The 27-year-old Djokovic is now two wins away from clinching the year-end No. 1 ranking for the third time in four years.
Also on Day 2 in London, the third-seeded Australian Open champion Wawrinka flattened the sixth-seeded former Wimbledon runner-up Berdych 6-1, 6-1 in a brisk 58-minute affair. Wawrinka broke his Czech counterpart five times while holding his quality serve throughout on Monday.
The world No. 4 Wawrinka had been stuck in a rut since losing in the U.S. Open quarterfinals, winning only one tour match since, but the Swiss played some of his best tennis of the year on Monday.
"I didn't expect to win that easy, for sure," said Wawrinka. "But I was ready to play well.
"I had a great week of preparation. Today, the start of the match was really important. That changed it completely."
This week's other four-player group, or Group B, features second-seeded Roger Federer (1-0), fourth-seeded U.S. Open runner-up Kei Nishikori (1-0), fifth- seeded home crowd favorite Andy Murray (0-1), and seventh-seeded Milos Raonic (0-1).
Nishikori, Raonic and Cilic are making their Tour Finals debuts this week.
On Tuesday, Federer will face Nishikori and Murray will battle Raonic. Federer handled Raonic and Nishikori upset Murray in straight sets on Sunday.
Federer, who is making a record 13th consecutive appearance at the Tour Finals and has an outside chance of capturing the year-end top ranking, holds the record for the most titles at this tournament with six.
Round-robin action will be staged here through Friday, followed by the semifinals on Saturday and lucrative final on Sunday.
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