Azarenka was booed off court at Wimbledon earlier this month after her defeat to Svitolina, with fans apparently perceiving she had snubbed her Ukrainian opponent by not advancing to the net for a handshake.

In fact, Svitolina did not offer a handshake - something she has declined to do with players from Russia and Belarus ever since the invasion of her homeland. Belarus is a key military ally of Moscow.

On Monday, tournament organisers in Washington aimed to pre-empt any possible repeat of the controversy by informing fans before the match there would be no handshakes.

"At the conclusion of the match there will be no handshake between the players," a message on an arena screen said beforehand.

"We appreciate your respect for both athletes during and following the match, and for your understanding during these difficult circumstances."

With that issue settled, it was left to the two rivals to serve up a hard-fought if error-strewn battle that saw no fewer than 17 breaks of serve before Svitolina finally prevailed 7-6 (7/2), 6-4.

Svitolina clinched victory by breaking Azarenka's serve in the 10th game of the second set.

A wild Azarenka backhand presented Svitolina with a match point which she duly converted on the first attempt after bludgeoning a forehand winner into the corner.

Azarenka saluted Svitolina's victory with a fleeting thumbs-up before heading off the court.