LONDON -- Andy Murray and Rafael Nadal both claimed convincing wins at their opening matches of the ATP World Tour Finals here on Monday.

Second-seeded Murray beat Spain's David Ferrer 6-4, 6-4 while Nadal brushed aside Stan Wawrinka 6-3, 6-2 in the day's second round-robin match.

Murray will take on Nadal in his next match-up and Ferrer play Wawrinka.

The 28-year-old Murray will seal the second place in the year-end world rankings for the first time should he win either of the remaining two group matches.

He will also guide Britain to fight in the Davis Cup final against hosts Belgium next week.

"It was a tough match with a lot of long rallies," said Murray. "He fought hard right to the end and made it extremely difficult."

Nadal, who has had a worst year of his career, won his first match against the fourth-ranked Wawrinka in their recent five clashes.

Wawrinka, who replaced Nadal as the French Open champion this year, made the perfect start with a break of serve to love but handed the initiative straight back in similar fashion, and looked increasingly frustrated as the evening wore on.

Fifth seed Nadal has shown encouraging form in recent months, reeling off nine of the last 11 games to clinch victory.

"Last year was tough," said Nadal. "I'm very happy to start like this, that's important for my confidence. The last couple of weeks I've been playing well."

"Without any doubt, this is one of the best tournaments in the world, in a great city. I'm very happy to start like this, that's important for my confidence. The last couple of weeks I've been playing well. I have the same motivation, the same spirit to keep improving my tennis."