Carlos Alcaraz began his bid to complete a career Grand Slam with an imperfect but entertaining 6-1, 7-5, 6-1 win over Kazakh Alexander Shevchenko to ease into the Australian Open second round on Monday.

Four-times major champion Alcaraz is targeting his maiden trophy at Melbourne Park to become the youngest man to capture all four Grand Slam titles and the 21-year-old went all guns blazing after a slightly nervy opening game.

"I always say that it's hard work," Alcaraz said.

"I try to bring the best of me every day. That's the secret. Every day I try to be a better person and better player."

The third seed, still fine-tuning a new service motion that he adopted in the off season, fended off a break point and then broke in the third game to take full control of the opening set which he wrapped up in double quick time.

French Open and Wimbledon holder Alcaraz found his range with some devastating winners on both flanks and went up 3-1 in the second set but world number 77 Shevchenko won the next four games as fans on Margaret Court Arena got behind the underdog.

Alcaraz switched back on and struck a fiery forehand winner to set up another break point and drew level in the 10th game as his opponent began to feel the intense pressure again and went on to surrender the set.

With the momentum having swung definitively, 2022 U.S. Open champion Alcaraz reeled off games in the third set and finished it off with a big ace on his fifth match point to book a second-round meeting with Japan's Yoshihito Nishioka.

"He's a really solid player," Alcaraz said.

"I have to be focused on my shots.... Hopefully I can enjoy the match, it's going to be tough. I'll try to produce some good tennis for people to enjoy."