Coco Gauff stepped up preparations for the Australian Open with an emphatic 6-3, 6-0 win over rising Czech Brenda Fruhvirtova at the Auckland Classic on Thursday to march into the quarter-finals. After a few issues at the start in which US Open champion Gauff dropped her first service game and had to save two break points on her third, the 19-year-old proved unstoppable in the battle of the teens. The 16-year-old qualifier Fruhvirtova, who beat world number 48 Anna Blinkova in the first round, won only 10 points in the second set of a match that was over in 70 minutes.