Karlovic, who turns 39 next month, came through the longest match of the tournament so far with 53 aces in a 7-6(3), 6-7(3), 7-5, 4-6, 12-10 victory over Japan’s Yuichi Sugita in four hours and 33 minutes.
“I‘m happy, but also very tired,” said 6’11” Karlovic, who towered over 5’9” Sugita. “I was already feeling it at the beginning of the third set, but I just focused on my serve.”
The Croatian, who will now take on Italian Andreas Seppi, will be the oldest player to compete in the third round since Australian great Ken Rosewall, aged 44, in 1978, when the draw was 64 players. Karlovic is the oldest player in the Australian Open third round since the advent of a 128-player draw in 1982.
Karlovic saved four break points in the second game of the deciding set, then broke in the 21st game of the set after Sugita made a forehand error. He finished the match with a backhand volley, his 110th winner.
Looking ahead to playing Seppi, Karlovic said, “It’s going to be very tough because he returns unbelievably. I will try to play my game and we will see. It’s going to be very hot and that will make my serve a little faster. But it will not be easy.”