MELBOURNE, Australia — Coco Gauff's retooled forehand and serve abandoned her in the worst way and at the worst time at the Australian Open. The unforced errors just kept accumulating, and so did the double-faults and break points, often followed by a palm placed over her eyes or a slap to a thigh.

No. 11 seed Paula Badosa of Spain upset American Coco Gauff, the No. 3 seed, in straight sets at the Australian Open quarterfinals.

Coco Gauff was defeated by Paula Badosa in the Australian Open quarterfinals on Monday, suffering a straight-sets loss that left fans stunned. With