By Martyn Herman
LONDON | Fri Nov 9, 2012 2:15pm EST
(Reuters) - World number one Novak Djokovic marched into the semi-finals of the ATP World Tour Finals with an unblemished record after completing his round-robin matches with a 6-2 7-6 win over Czech Tomas Berdych on Friday.
The Serb, winner of the year-end showpiece in 2008, followed his victories over Jo-Wilfried Tsonga and Andy Murray with another clinical performance in front of a 17,000 sell-out crowd at the O2 Arena guaranteeing top spot in Group A.
World number three Murray will join Djokovic in the semi-finals as long as the Briton avoids losing in straight sets to Tsonga in the evening match.
Defeat eliminated Berdych who was left to rue three squandered set points in the second set.
Djokovic, whose thoughts have been with his sick father, dominated the first set with precision hitting and then showed his mettle to fend off a Berdych fightback as he won all three group matches at the event for the first time.
"I didn't want to think about scenarios or calculations, I'll leave that to other people," said the 25-year-old, who was guaranteed a top-two finish in the group once he had pocketed the opening set.
"I try to do my job and win on the court, I played a really good match but I thought he served better towards the end of the second set.
"I was fortunate to come back and win in straight sets."
Fifth seed Berdych can now prepare for the Czech Republic's Davis Cup final against holdersSpain in Prague.
"Next week, it's another week, another event, another big thing," Berdych told reporters. "I hope the best moment (of my year) is still to come."
DOMINANT DJOKOVIC
Djokovic, who will end a second successive year at the top of the rankings after another outstanding season, had won 10 of his 11 matches against Berdych and it was easy to see why in the first set as he consistently outmanoeuvred his opponent.
Berdych likes nothing better than to dictate the rallies with his clubbing forehand but Djokovic's superior movement and variety kept the Czech off balance.
Two service breaks saw Djokovic cruise through the opening set and when he broke again early in the second there looked no way back for Berdych, whose sole win in their previous matches was at Wimbledon in 2010 when he was runner-up to Rafa Nadal.
To his credit Berdych hit back immediately to break serve when Djokovic missed a volley and from then on he pushed the Serb all the way.
Djokovic was made to sweat to hold serve at 5-6 and when Berdych thundered down an ace to lead 6-3 in the tiebreak a decider looked imminent.
Typically, Djokovic did not flinch.
He won the next two points on serve and then a stunning service return forced Berdych to net.
Djokovic completed victory on his first match point when his opponent ballooned a forehand long after one hour 37 minutes.
Swiss defending champion Roger Federer has already reached the semi-finals from Group B and will be joined in the last four by either Juan Martin del Potro or David Ferrer.
(Editing by Tony Jimenez and Ken Ferris)
