US Open champion Coco Gauff is about to enter the most significant phase of her season and she has to be concerned by her form.
Gauff was upset 6-4, 6-1 by fellow 20-year-old Diana in the WTA 1000 event in Toronto, with her worrying slump in form showing no sign of ending.
It was the first win against a top ten opponent for Shnaider and she is through to her first quarter-final at a WTA 1000 event.
The news for Gauff is not so positive as since reaching the semi-finals and losing to eventual champion Iga Swiatek at the French Open in June, Gauff has slipped to a series of disappointing defeats.
She was beaten by fellow American Emma Navaro in a shock last-16 defeat at Wimbledon and then lost against Donna Vekic in another surprise result at the Olympics.
Gauff would have been hoping a return to her favourite North American hard courts would have fired her back into winning form, but the defeat against Shnaider continued an alarming slide in fortunes.