World number one Iga Swiatek survived a tough examination against Jule Niemeier on Monday to reach the second round of the Australian Open.

The 2022 French and US Open champion was far from the fluent best that took her to a 37-match win streak last season, needing an hour and 59 minutes to see off the dogged German 6-4, 7-5 on Rod Laver Arena.

Swiatek is looking to add the third leg of a career Slam of all four majors in Melbourne but after edging a tight first set was broken at the start of the second by the powerful German world number 69.

Niemeier was coming off the biggest season of her career in 2022 where she made the quarter-finals at Wimbledon and led Swiatek by a set and a break in the last 16 at the US Open.

But having broken Swiatek in the first game of the second set the 23-year-old faltered when serving at 5-4 and Swiatek pounced to level before taking the match.

"Honestly, I wanted to be focused on myself because I know that Jule serves amazing and was really pushing, putting pressure on me," said Swiatek, who landed only 49 percent of her first serves.

"So I'm pretty happy that I got through this match because the first round is always tricky, and I guess an opponent like Jule makes it even more tricky."

The win took her win-loss record in first-round Grand Slam matches to 15-1 a year after recording her best result at Melbourne Park, eventually losing to Danielle Collins after a run to the semi-final.

The three-time major winner -- she also triumphed at Roland Garros in 2020 -- will face Colombia's Camila Osorio in the second round.