Djokovic reaches Tour Finals title match

Top-ranked Novak Djokovic reached the title match of the season-ending ATP World Tour Finals Sunday, posting a three-set win over Juan Martin del Potro. The Serbian world No. 1 dropped the first set against the Argentine but then stormed back for a 4-6, 6-3, 6-2 victory at the London event. He now goes on to Monday's championship match against either Roger Federer or Andy Murray, who were set to play in Sunday's second semifinal contest. After losing the first set, Djokovic found himself trailing del Potro 2-1 in the second frame when he began to turn things around, breaking the Argentine on his fourth chance of the game and sixth of the match. After that it was all Djokovic, who has won the season-ending event once previously, in 2008. Federer is the two-time defending champion.