World number two Rafael Nadal lost his third match in a row at the ATP World Tour Finals, leaving the tournament without having won a set.
This time defeat was at the hands of world number three and defending champion Novak Djokovic, the score 7-6 (7-1) 6-3. However, despite the win, Djokovic failed to reach the semi-finals.
The final four are Federer, Soderling, Davydenko and del Potro, the semis being played on Saturday.