By Shrivathsa Sridhar and Ian Ransom MELBOURNE (Reuters) -Defending champion Aryna Sabalenka and Madison Keys made sluggish starts on Thursday but sealed contrasting victories to set up an Australian Open final showdown that will pit two of the game's heavy hitters against each other.

When Madison Keys finally finished off her 5-7, 6-1, 7-6 (10-8) upset of No. 2 Iga Swiatek in a high-intensity, high-quality Australian Open semifinal on Thursday night, saving a match point along the way,