Melbourne, Australia: Agnieszka Radwanska powered past American Christina McHale in straight sets at the Australian Open Monday, showing no sign of the injury that forced her out of the Brisbane International.

The Pole, who this month eased above Maria Sharapova to be fourth on the world rankings, came through her opening round match under the blazing Melbourne sun 6-2, 6-3.

There was no inkling of the niggly left leg problem that saw her withdraw from the Brisbane warm-up event this month, with the 26-year-old moving freely on Margaret Court Arena as she continued her solid form.

"I had a very good off-season and I just hope I can play good tennis here," she said after the 80-minute win.

"I always feel good in Australia, I love the crowd, I always feel comfortable out on court." 

Radwanska has been on a roll in recent months, winning the biggest title of her career by downing Petra Kvitova 6-2, 4-6, 6-3 at the season-ending WTA Finals in Singapore.

She then started her year by winning the Shenzhen Open before pulling out of Brisbane to rest her leg after five matches in a week.

While Radwanska has long been among the elite women's players, she has yet to break through at the majors, coming closest at Wimbledon in 2012 when she was runner-up to Serena Williams.

She broke early against McHale to take a 2-0 lead, but threw away her advantage when she let the American break back in a see-sawing first set.

It was quickly 3-1 in the Pole's favour as she pushed her opponent around the court and then landed a decisive cross-court winner to go 3-1 in front, but her service game was again exposed by McHale who clawed back into the match.

Undeterred, the composed Radwanska broke again and finally held serve with one more break handing her the set.

It was an exhausting 39-minute workout as the temperature crept up to 34 Celsius (93 Fahrenheit), with the players draping ice towels around their necks at the changeovers.

The Polish star took charge of the second set with an early break before once again opening the door for McHale by failing to hold her own serve.

But as the set wore on and McHale tired, Radwanska put her foot to the floor and showed her experience to grind out victory.  

She next plays Canadian Eugenie Bouchard or Serb Aleksandra Krunic as she seeks to go one better than the semi-finals, her deepest run at Melbourne Park which came in 2014.