Serbia's Novak Djokovic, the defending champion and world No. 1, rolled over American Ryan Harrison 6-1, 6-2, 6-3 on Wednesday in the second round of the Australian Open.

"This was definitely a better performance than the first round. You know, I managed to play in a very high level already in the second round of a Grand Slam, which is very encouraging for next challenge," Djokovic said after the match.

The next opponent for Djokovic, who has not lost a set in the tournament, will be Czech tour veteran Radek Stepanek, who beat Spain's Feliciano Lopez 6-2, 6-2, 6-4 on Wednesday.

Djokovic needed just 91 minutes to notch his third career win against Harrison, who he had previously defeated at Cincinnati in 2011 and Wimbledon last year, never losing a set to the American.

The Australian Open, the year's first Grand Slam tournament, began on Monday in Melbourne. EFE