Novak, Andy in semis

Novak Djokovic extended his win streak to 20 at the Paris Masters on Friday, defeating Tomas Berdych 7-6 (7/3), 7-6 (10/8) to reach the semifinals.

Andy Murray and David Ferrer also made it through to the last four in the bottom half of the draw on a day of marathon clashes, but Rafael Nadal crashed out to Stan Wawrinka.

The straight sets victory for world number one Djokovic also meant that he has now won 28 sets in a row -- the best run of his career -- dating back to the US Open final in early September.

But he had a battle on his hands against fifth-seeded Berdych, a winner in Paris 10 years ago when he was just 20.

Neither player could manage a break of serve, the first time that has happened to Djokovic in 680 career wins, according to ATP statistics.

Despite having lost all 16 of their previous hardcourt matchups, the towering Czech had the better of the first set behind a powerful display of serving and forehand blockbusters.

Berdych kept his nose in front and his chance came with a set point at 6-5 up only for Djokovic, the top seed and defending champion, to produce a big first serve and a forehand winner off the blocked return.

The tie-break, however, was dominated by the Serb winning four of the first five points to take control.

Serves again dominated in the second set with both men holding firm to bring up a second straight tie-break which Djokovic edged 10/8 despite Berdych having another set point.