Five-setters make matches memorable, says Novak Djokovic, citing the tension and effort involved in such encounters.

The world No. 1 pointed to his defeat against Stanislas Wawrinka in the Australian Open quarterfinals as one of the significant matches of his season.

"We get to play five sets in Grand Slams and Davis Cup only. It's pretty special obviously if you go all the way to a fifth setter," Djokovic said following his U.S. Open fourth-round victory. "This year I have lost in fifth set against Stan in Australia. It was one of the matches that stand out this year that I play in five sets that I can remember."

The impact is bigger because such matches are only contested at big tournaments, he observed.

"When you go the distance, especially against one of the top players, you know, very few points can decide a win," Djokovic said. "That's obviously a combination of mental toughness and physical strength that give you the win."