Britain's Katie Boulter saved four match points but ultimately fell to Daria Kasatkina in the first round of the Australian Open.

Boulter, ranked 371 but using her protected ranking in Melbourne, lost 6-1 6-4 to the Russian.

The 24-year-old made 18 unforced errors in the first set against former top-10 player Kasatkina.

She fought back from a 5-2 deficit in the final set before Kasatkina closed out victory in 71 minutes.

Boulter had beaten promising American teenager Coco Gauff in the Gippsland Trophy as part of her Grand Slam preparations.

However Kasatkina, now ranked 71 after a difficult few years, proved too much for Boulter.

Boulter is the only Briton in action on the first day at Melbourne Park.

She did not help herself in a error-strewn first set, hitting just two winners as Kasatkina blazed past her in 23 minutes.

After saving a break point in her opening service game of the second set, Boulter was broken in the fourth game and found herself serving to stay in the match at 5-3.

It looked to be over as Boulter went 0-40 down on her serve, handing Kasatkina three match points, but the Briton rallied to win the 10-minute game and cling on.

However, Kasatkina was able to take advantage when Boulter's serve faltered again to set up a second-round meeting with either seventh seed Aryna Sabalenka or Viktoria Kuzmova.

Serena Williams and Naomi Osaka both registered quick victories on the opening day at Melbourne Park.

The first Grand Slam of the year was delayed by three weeks to allow players to quarantine on their arrival.