Stanislas Wawrinka won the opening match of the week on Monday as he made his debut at the World Tour Finals with a 6-3, 6-7 (0-7), 6-3 round-robin defeat of Tomas Berdych.

Wawrinka, one of two Swiss in the eight-man field along with six-time champion Roger Federer, held his nerve on the big occasion, winning in just under two and a half hours with 11 aces and 43 winners and by breaking Berdych twice.

A second group match due later Monday was to pit Argentine Juan Del Potro against Frenchman Richard Gasquet, who appeared at the year-end event in 2007 when it was played in Shanghai.

Wawrinka earned victory on his first match point as Berdych fired a forehand wide, his 31st unforced error.

The Swiss improved to 8-5 over the Czech, who is playing the season wrap-up for the fourth year in succession. Berdych was the only player in the field without an ATP title this season.

Wawrinka’s win was his 50th of the season, the best result of his career.

“In the first set, we were both a bit tight,” he said after he needed five set points to finally secure the opener. “But I focused on my game. It was not easy my first time here.

“For sure, I was nervous on the court, but he was nervous, too. I can feel it. When I’m in that situation, I have to focus on my game plan, on what I want to do, how I’m going to do it.” The Swiss lost the second set to love in the tiebreaker as Berdych found form, but Wawrinka got a break for 3-1 in the third set on his way to taking the victory.

“When I sat down after the second set, I was still thinking I was the best player on the court,” he said. “I had some chance. I was playing good. I had few chances to break him but didn’t find them.

“I had to focus again on my serve and start maybe the third set a little bit more aggressive to show him that I’m going to try to win the match and not let him do it.”

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