Coco Gauff draws on Tiafoe and ‘delusional’ self-belief in US Open escape

• American rallies from brink to defeat Andreeva

• Gauff survives 12 double faults in three-set escape

Coco Gauff has played far cleaner matches than on Wednesday afternoon. But few players today on the women's tour have become better at finding answers on the fly when almost nothing is working for them.

The 22-year-old American's serene march through the US Open women's draw hit extreme turbulence early in her quarter-final clash with fifth-seeded Mirra Andreeva inside Arthur Ashe Stadium. She dropped the first four games before surrendering the opening set in 26 minutes, ending a streak of 20 consecutive sets won dating back nearly a month. She piled up 12 double faults and 42 unforced errors, the majority off a forehand in open revolt. She found herself one point from defeat not once but twice during a hairy second-set tiebreaker.