Andy Murray and Rafael Nadal produced emphatic responses to the critics as they kicked off their ATP Tour Finals campaigns in dominant fashion on Monday.
Murray silenced the doubters who claimed he was distracted by dreams of Davis Cup glory with a gritty 6-4, 6-4 win over David Ferrer, while Nadal, beset by problems during the worst year of his career, showed he isn't finished yet with a 6-3, 6-2 thrashing of French Open champion Stan Wawrinka.

Former Wimbledon champion Murray has made it clear his main priority in the closing weeks of the season is Great Britain's attempt to win the Davis Cup for the first time since 1936 in their first final since 1978.

Britain face Belgium in the final on clay in Ghent next week and Murray had initially suggested he might pull out of the Tour Finals to fine-tune his preparations for the Davis Cup.

After learning of potential sanctions from the ATP if he withdrew, Murray settled for spending most of last week practising his clay-court game across London at Queen's Club before arriving at the O2 on Friday.

It was hardly ideal preparation and inevitably Murray's commitment against Ferrer was under close scrutiny from cynics who doubted whether the world number two really wanted to risk injury with the Davis Cup just around the corner.
But Murray assuaged those worries with a typically whole-hearted 90-minute display to see off Ferrer in his opening group match in the prestigious season-ending event.

"If I didn't play here, I would have gone three weeks or something without playing a match before the Davis Cup Final," Murray said.

"Obviously it's a different surface here, but playing matches against the best players in the world is also fantastic preparation.

"I feel good just now. Hopefully I can perform well here and in Belgium."

While Murray was unable to win a Grand Slam this year, his impressive consistency over the last 11 months has brought him to the verge of finishing second in the year-end world rankings for the first time.
The 28-year-old will now be guaranteed that milestone if he wins one of his remaining two group matches against Nadal and Wawrinka.

- Fallow period -

After winning at least one Grand Slam title in each of the last 10 years, 2015 has been a fallow period for Nadal.

The injury-plagued 14-time Grand Slam winner saw his long reign as French Open champion ended by Novak Djokovic in the quarter-finals and also suffered shock early exits from Wimbledon and the US Open.

Nadal, 29, has lost a career-worst 19 matches this season and at one stage he slumped to 10th in the world -- his lowest position since 2005.
In contrast to Nadal's struggles, Wawrinka has been in the best form of his life, winning four titles including his second Grand Slam, and the world number four was hoping to cap his year by reaching the final of the Tour Finals for the first time.

Wawrinka, 30, made the perfect start against Nadal, who had lost three of his last four encounters with the Swiss, as he earned a break in the opening game, but that was the cue for the Spaniard to spring into action.

Nadal broke back in the next game and wore down Wawrinka in a marathon eighth game that lasted nearly seven minutes to secure a second break that settled the set.

The Tour Finals is one of the few major prizes to have escaped Nadal in his glittering career and winning it this week would at least partially salvage his disappointing year.

Aided by 35 unforced errors from Wawrinka, Nadal took the first step to that goal as he broke twice in the second set to seal the win.

"I'm very happy to be back, the last year has been tough," Nadal said.

"I'm very happy to start like this, that's important for my confidence.

"I have the motivation to keep improving my tennis."
Source: AFP