Rafael Nadal began his quest for a record 21st Grand Slam championship with a 6-1, 6-4, 6-2 win over American Marcos Giron in the first round of the Australian Open on Monday.

The 35-year-old Spaniard outplayed the 28-year-old Giron, hitting seven aces and winning 84 percent of the points on hisfirst serve. Nadal, the No. 6 seed, capitalized on five of nine break-point opportunities and hit 34 winners to 10 for Giron.

On the year, Nadal moved to 4-0 after winning the Melbourne Summer Set last week, an encouraging sign for him as he attempts to rebound from a foot injury that sidelined him most of the second half of 2021.

"It's been a very challenging few months ... tough moments with a lot of doubts -- there still are doubts," Nadal said. "But I am here and I can't be happier to be back in Australia in this amazing stadium.

"You never know when you come back from injury, which unfortunately I have a lot of experience with, how things will be, so you have to take it day by day. You have to forgive yourself if things aren't going the proper way."

Nadal, who won the 2009 Australian Open, is attempting to join Novak Djokovic as the only man to win all four Grand Slam tournaments twice. Standing in his way in the second round will be German qualifier Yannick Hanfmann, who topped Australia's Thanasi Kokkinakis 6-2, 6-3, 6-2 in two hours and eight minutes.

Also advancing to the second round was No. 3 seed Alexander Zverev of Germany, who ousted compatriot Daniel Altmaier 7-6 (3), 6-1, 7-6 (1) behind 53 winners in their two hour, 38-minute match.

"Not much went to plan today to be honest except that I won," Zverev said in a post-match interview on the court. "But that is how it is sometimes. It is the first round of a very long tournament and you are not always going to play your best tennis. It was a good match for me to get into the tournament and hopefully the next round will be better."

Zverev, 24, is the world's No. 3 player but is still seeking his first Grand Slam championship among 19 tour titles.

Other seeded players to win Monday were No. 7 Matteo Berrettini of Italy, No. 10 Hubert Hurkacz of Poland, No. 14 Denis Shapovalov of Canada, No. 16 Cristian Garin of Chile, No. 17 Gael Monfils of France, No. 18 Aslan Karatsev of Russia, No. 19 Pablo Carreno Busta of Spain, No. 23 Reilly Opelka, No. 25 Lorenzo Sonego, No. 28 Karen Khachanov of Russia and No. 31 Carlos Alcaraz, an 18-year-old from Spain.

In the day's upsets, American Sebastian Korda ousted No. 12 seed Cameron Norrie of Great Britain in straight sets and No. 30 Lloyd Harris of South Africa was beaten by Australian Aleksandar Vukic.