Novak Djokovic capped off his season by defending his ATP World Tour Finals title with an impressive 6-3, 6-4 win over Rafael Nadal on Monday night. There's no doubt Djokovic is the man to beat on indoor hard courts. And just for the record, his 22 consecutive wins to finish 2013 matched top-ranked Nadal's best stretch of the year. Djokovic's winning run started after a U.S. Open final defeat to Nadal, and during a span when the Spaniard replaced him atop the rankings. More...