Murray and Djokovic in semis
Andy Murray moved safely through to the semi-finals of the Barclays ATP World Tour Finals in London with victory over Jo-Wilfried Tsonga.
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The Scot knew prior to his final group match that one set would be good enough after Novak Djokovic made it three victories out of three against Tomas Berdych.
And he took any potential drama out of the situation by winning the opening set, which in turn ended Tsonga's hopes of progression, before going on to clinch a 6-2 7-6 (7/3) victory in an hour and 36 minutes.
It is the second time the 25-year-old has reached the last four at the O2 and the third time at the tournament as a whole.
Murray made the semi-finals in his first appearance at the Tour Finals in 2008 in Shanghai, losing to Nikolay Davydenko, while two years ago he came out on the wrong end of an epic clash with Rafael Nadal.
This time he is likely to have to defeat Roger Federer and Djokovic if he wants to end his season with a trophy, although his last-four opponent will not be confirmed until the final Group B matches on Saturday.
Murray said: "It's quite a tough scenario when you know you need to win one set. I got off to a good start so that helped, and at the end of the second set there were some good rallies so that was nice.
"Ivan (Lendl, Murray's coach) said to me before the match, 'Just forget you only need to win one set,' so then I was thinking about it. It is hard."
Djokovic had made it three wins out of three as he saw off Berdych 6-2 7-6 (8/6), saving three set points in the second set.
Berdych had beaten Djokovic only once in 11 previous meetings, in the semi-finals of Wimbledon in 2010, and he was soon under pressure.
Djokovic's famed returns were rushing the Czech and, although he clawed his way back from 0-40 in the third game, a fourth chance arrived and the world number one took it.
Djokovic, whose best performance at the O2 was a semi-final appearance in 2010, looked extremely sharp and he made it five games in a row before Berdych finally stopped the rot.
The top seed comfortably held to win the set, though, and with that assured himself qualification for the last four.
Berdych appeared to have no answer when Djokovic broke again in the third game of the second set but he began to take the fight to his opponent a bit more and hit back to level at 2-2.
The crowd were keen to see a good match and got behind the Czech, who saved more break points to edge ahead in the set.
Berdych was beginning to match Djokovic from the back of the court and making his extra power count, and he made a flying start to the tie-break, winning five of the first six points.
But Djokovic did not give up and saved two set points on his own serve before another trademark return at Berdych's feet levelled matters at 6-6.
The top seed then added a fourth point in a row and clinched victory when Berdych fired a return long.
Djokovic has built a reputation for clawing his way back from difficult positions in sets and matches.
He said: "I just try to have simple thinking, to fight for every point. Sometimes it doesn't work. I'm glad it worked today.
"For the first time I won all three matches in my group. This is very encouraging for me, so I will try to focus on the semi-final now."
Berdych was a little disappointed with how he played and was reluctant to think about what might have been.
He said: "I had some chances in the tie-break. If I had been able to make it, tried to push him for the third set, then maybe I would have got another chance. But it didn't happen. It wasn't one of my best matches with him."