Novak Djokovic remains top of the world rankings despite his surprise defeat to lucky loser Lorenzo Sonego in Vienna last week, the ATP announced on Monday.
Djokovic made his return to the court in Austria having not played since Roland Garros and has now spent 293 weeks as the world's best player, edging closer to Roger Federer's record of 310.
The Serb 17-time Grand Slam winner is virtually guaranteed to equal Pete Sampras's record of securing a year-ending top ranking for the sixth time with second-placed Rafael Nadal unlikely to play at Sofia this month.
Italian Sonego rises to a career-best of 32nd after inflicting on Djokovic the worst three-set loss of his career.
This week, Nadal is in action at the Paris Masters and said on Sunday he was not worried about injuries which have ended his last two visits to the tournament.