Ash Barty moves through to Australian Open quarterfinals with straight-sets win over Amanda Anisimova.

Ash Barty has marched into the Australian Open quarterfinals for the fourth straight year after dispensing of American Amanda Anisimova in straight sets.

Despite conceding her first service break of the tournament, Barty endured few nervous moments as she completed a 6-4, 6-3 triumph on Rod Laver Arena.

Both Barty and Anisimova saved break points early in the first set, but the Australian turned up the pressure in the fifth game.

From three break points, two were saved, but Barty won the game when Anisimova went long with a forehand return.

More than once during the second game, she found herself poorly positioned on the baseline, allowing Anisimova to capitalise with forehands to the open court.

Anisimova seemed to be on the verge of holding when she was 40-15 up, but she lost the next four points to hand over another break to Barty