Swiatek had an up-close look, losing to Gauff in the WTA Finals in Saudi Arabia in November and in the final of the United Cup team event last week in Sydney. Both were straight-set results and came after Swiatek had led their head-to-head series 11-1.

It was a meaningless hit-and-giggle session, so Coco Gauff was calling out how fast she would try to hit some serves.

Coco Gauff is the favorite to win the Australian Open and has been getting into the swing of things by adding a new element to her game - a grunt.