NEW YORK (Reuters) -Novak Djokovic's bid for a 21st major title that would complete a calendar-year Grand Slam picked up pace on Thursday as the world number one cruised into the U.S. Open third round with a 6-2 6-3 6-2 thrashing of Tallon Griekspoor.

Having shaken off the rust in a spotty four-set opening match against 18-year-old Holger Rune on Tuesday, Djokovic was sharper and much more focused against the 25-year-old Dutchman.