The Pole was forced to play her best tennis to see off her 41st-ranked opponent in a rematch of the 2020 French Open final and set up a clash against 2022 finalist Danielle Collins.

"Really happy, it's not easy to play the first round, especially in the first Grand Slam of the season," Swiatek said in a courtside interview.

"It was not easy at the beginning to find my rhythm and I felt a little bit off. I feel like Sofia did everything to keep it that way.

"I'm happy that I managed to get my level up in the second set."

The match started in blazing sunshine and Kenin was soon playing with the strutting confidence that helped her clinch her only Grand Slam title on the same Rod Laver Arena court four years ago.

The 25-year-old American snatched an early break only to hand it back with successive double faults but again feasted on Swiatek's second serve for another break with a monster of a backhand down the line.

Swiatek has not won four Grand Slam titles without being able to problem-solve, however, and again put the set back on level terms at 5-5, had a set point at 6-5, and dominated the tiebreak.

Kenin, who has plumbed the depths since her 2020 Melbourne triumph and was ranked 235 in the world at the start of last season, maintained her level at the start of the second stanza and her clean-striking was soon causing Swiatek more problems.

The three-time French Open champion always seemed to have the cooler head in the clutch moments, however, and grabbed a break for 3-2 as a frustrated Kenin looked increasingly frequently to her box for answers.

Swiatek saved two break points in the next game before cruising to the finish line to reach the second round for the sixth straight year and keep alive her quest for a first Australian Open title.