Djokovic advances to ATP Finals semis
LONDON (AP) - Defending champion Novak Djokovic joined top-ranked Rafael Nadal in the semifinals of the ATP World Tour Finals by defeating Juan Martin del Potro 6-3, 3-6, 6-3 on Thursday.
Djokovic, undefeated in last year's Finals, improved to 2-0 in Group B with his victory over the hard-hitting Argentine. Djokovic defeated Roger Federer in his opening match.
Nadal qualified from Group A on Wednesday when he beat Stanislas Wawrinka to clinch the season-ending No. 1 ranking for the third time.