Nadal, Sharapova advance in straight sets at Australian Open

"I think it's very easy to be in a position where things are flowing, you know, you're doing all the right things, she's making a few errors, you're comfortable, easy to get complacent, and, you know, complacency is not great. I was glad that I did the right things from the beginning till the end." Up next for Sharapova is Rebecca Peterson, who beat Sorana Cirstea, 6-4, 6-1.

Also advancing were 2017 U.S. Open champion Sloane Stephens, No. 11 Aryna Sabalenka, No. 19 Caroline Garcia, No. 29 Donna Vekic and No. 31 Petra Martic.

Danielle Collins advanced to the second round of a major for the first time following a 2-6, 7-6 (5), 6-4 win over No. 14-seeded Julia Goerges, who won the title in Auckland to start the season.

Katie Boulter earned the distinction of winning the first 10-point tiebreaker under the Australian Open's new system for deciding sets.

Boulter beat Ekaterina Makarova 6-0, 4-6, 7-6 (6), including 10-6 in the tiebreaker. The new rule was introduced to ensure matches don't get too lengthy — previously the third set in women's matches and the fifth set in men's matches at the Australian Open had to be decided by a two-game advantage.

Fifth-seeded Kevin Anderson won his first match at Melbourne Park since 2015 when he beat Adrian Mannarino 6-3, 5-7, 6-2, 6-1. Also advancing on the men's side were No. 19 Nikoloz Basilashvili and No. 26 Fernando Verdasco.

Defending champions Caroline Wozniacki and Roger Federer were scheduled to play night matches later Monday.