Robin Soderling followed up his ATP World Tour Finals defeat of Rafael Nadal with a straight sets win over Novak Djokovic at London's O2 Arena.

The Swede, who is only playing in the season-ending event after Andy Roddick pulled out injured, all-but sealed his place in the semi-finals with a 7-6 (7-5) 6-1 win over a tired-looking Djokovic.

Djokovic, the world number three, had beaten his 25-year-old opponent in all of their five previous meetings.

But only four massive serves prevented Soderling from being broken in the third game.

With Soderling leading at 5-4 Serbia's Djokovic recovered from 0-40 down to eventually take the first set into a tie-break where mini-breaks were traded before Soderling emerged victorious.

Soderling, who is the only person to have ever beaten Nadal at the French Open, wrapped up the second set in quick order as Djokovic, the form player going into the ATP World Tour Finals, showed signs of fatigue.

Tonight Nadal and Nikolay Davydenko, who both lost their first group B round-robin matches, play each other.

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