Top seed Iga Swiatek avoided an early Australian Open exit by turning around a double break deficit in the deciding set to beat Danielle Collins.

Poland's Swiatek trailed 4-1 before showing fight and composure to win the second-round match 6-4 3-6 6-4.

After taking her third match point, a relieved Swiatek dropped her racquet to the court before hiding her head underneath a towel.

"I was in the airport already," said the four-time Grand Slam champion.

"I wanted to fight until the end. I knew she would play perfectly but it would be hard to keep that level and I wanted to be ready when mistakes came.

"I did that and I'm proud of myself because it wasn't always that way."

Swiatek, 22, has emerged as the WTA Tour's dominant player in the past two years, leading the world rankings for most of that time and adding three more majors to her tally.

Three of her four Grand Slam triumphs have come on the French Open clay, with the other on the US Open hard courts, but her attempt to add the Australian Open title this year has been complicated by a tough draw.

After beating 2020 champion Sofia Kenin in the first round, she faced another stern test against the uncompromising Collins, a finalist at Melbourne Park in 2022.

The American has dropped to 62nd in the world but brought her best game to unsettle Swiatek with her power.

Using her devastating backhand to great effect, Collins looked set to inflict Swiatek's earliest exit at a Grand Slam since the 2019 US Open.

However, Collins was unable to keep her nerve as the pressure of the finishing line approaching overwhelmed her.

Looking tight, she lost serve for 4-2, could not convert three break points the next game and lost her serve again as Swiatek turned the deficit into a 5-4 advantage.

Swiatek held two match points at 15-40 - missing one with a volley into the net and the other with a backhand from the baseline - but was given a third opportunity when Collins dragged a cross-court backhand way wide.

This time she took it, scrambling to reach a dropshot after a long rally and pushing a backhand down the line.