Mackenzie McDonald KOs Rafael Nadal in Australian Open's 2nd round

Mackenzie McDonald knocked out defending champion Rafael Nadal in the second round of the Australian Open on Wednesday (Australia time), rolling to a 6-4, 6-4, 7-5 victory in Melbourne.

Nadal, the tournament's top seed, hadn't exited a Grand Slam event this early since falling in the first round of the 2016 Australian Open. The 36-year-old Spaniard has a men's-record 22 Grand Slam titles, including two last year, the Australian Open and the French Open.

McDonald, a 27-year-old California native, is ranked 65th in the world. He has never reached the quarterfinals of a major tournament in 17 previous attempts. Just to reach the matchup with Nadal, he needed five sets to get past countryman Brandon Nakashima on Monday.

McDonald finished with a 14-6 edge in aces. Each player had 42 winners, but Nadal committed 31 errors while McDonald gave away only 22 points.

"He's an incredible champion," McDonald said of Nadal. "He's never going to give up, regardless of the situation, so even closing it out against a top guy like that is always tough. I kept focusing on myself in the end and got through."

Nadal's loss gives an opening to Serbia's Novak Djokovic to tie for the men's Grand Slam mark. Djokovic has 21 major titles, including last year's Wimbledon crown.

Djokovic, who is seeded fourth, had no trouble in his second-round match at Melbourne on Wednesday, dispatching Spain's Roberto Carballes Baena 6-3, 6-4, 6-0.