With 64 wins out of 66 matches this year and three Grand Slams, Serbia's Novak Djokovic has already earned a record for prize money in a single season following his US Open championship on Monday. The number one player in the world has earned $10.6 million this year, more than any person ever in a full season of men's tennsi, the ATP World Tour said on Wednesday. Rafael Nadal last season and Roger Federer in 2007 both came close, each raking in around $10.2 million. For a whole season. By beating Nadal in the US Open final Monday night, Djokovic got a check for $2.3 million: $1.8 million for winning the tournament, plus a $500,000 bonus for finishing second in the US Open Series Standings, which takes into account results at hard-court tuneup tournaments. Djokovic started the year with a 43 match winning streak before losing to Federer at Roland Garros in the semifinals. Since then, his only loss was to Andy Murray, retiring with a sore shoulder in the second set. BM