British number one Katie Boulter lost in straight sets against Aryna Sabalenka in the third round of the Canadian Open.
The second seed from Belarus won 6-3 6-3 in one hour 23 minutes in Toronto but Boulter produced an encouraging performance with the US Open starting in two weeks' time.
The 28-year-old created four break points against the world number three but was unable to convert any of them.
Boulter, who reached the quarter-finals at the Olympic Games in the women's doubles, will play her final warm-up tournament before the US Open at next week's Cincinnati Open.