Djokovic and Federer claim opening day wins at ATP World Tour Finals

Novak Djokovic brushed aside Kei Nishikori in his opening match ©Getty Images

Serbia’s Novak Djokovic brushed aside the challenge of Japan’s Kei Nishikori on the opening day of the 2015 ATP World Tour Finals at the O2 Arena in London.

Djokovic began the tournament ensured of ending the year as the men’s world number one having won three of the four Grand Slam titles in 2015, but the 28-year-old is chasing a record fourth straight win at the season-ending event which features the top eight players.

A blistering start to the match saw Djokovic move into a 3-0 lead and he kept the pressure on an overwhelmed Nishikori, the lowest ranked qualifier playing at the week-long competition.

Having breezed through the opening set 6-1, the momentum remained with the Serbian star in the second as Djokovic continued to dismantle Nishikori’s serve with ease to claim a rapid straight sets 6-1, 6-1 triumph over the 2014 US Open runner-up.

"Undoubtedly it has been the best season and the best year of my life - I became a father and I got married,” Djokovic said following his victory.

“Those are the kind of trophies and milestones that mean the most to me.

"I've been experiencing the peak time right now of my abilities, I was very consistent with my results, 2011 and 2015 definitely stand out.”

Roger Federer began his pursuit of a seventh ATP World Tour Finals title with a straight sets win ©Getty Images

Djokovic was joined at the top of the Stan Smith Group, named after America's two-time Grand Slam winner, by Switzerland’s Roger Federer after he claimed a straightforward win over the Czech Republic’s Tomáš Berdych.

Berdych had begun the better of the pair, breaking in Federer’s opening serve game, but the 17-time Grand Slam winner quickly drew level and eventually claimed the first set 6-4.

Federer, winner of the World Tour Finals title on six occasions, dominated the remainder of the contest to emerge as a 6-4, 6-2 victor.

The doubles competition began with a major surprise as India’s Rohan Bopanna and Romania’s Florian Mergea, the lowest ranked pairing, overcame top seeds Bob and Mike Byran of the United States 6-4, 6-3.

Britain’s Jamie Murray and Australia’s John Peers claimed a thrilling victory over Italy’s Simone Bolelli and Fabio Fognini in their tie, with pair triumphing 7-6, 3-6 11-9.