It also continues an encouraging upturn in results for Watson, who reached the semi-finals at Eastbourne last week following impressive wins over defending champion Dominika Cibulkova, as well as Barbora Strycova and Anastasia Pavlyuchenkova, ranked 23rd and 17th respectively.
Two years ago at the same stage, the girl from Guernsey came within two points of knocking out Serena Williams only to lose in three sets. Yet in the meantime Watson has essentially known only loss of form, injury and a vertiginous drop in ranking places, so, coming on the back of a... I've got to expect her to raise her level and to try something new, and she did.
"It's always going to change and I was pleased with how I remained calm and just kept doing what I was doing".
Watson admits it's a lifetime ambition to make it into the last 16 of a major and her coach Morgan Phillips is just as desperate for her to make it to manic Monday. That's the best atmosphere I've ever played in my life.
"It's been one of my goals forever", she said.
Azarenka is now back on the circuit after taking time off to have a baby and was too good for 15th seed Elena Vesnina.
"You don't get to where she's got to in her career without, you know, being a really good player".
"I look forward to playing her". She's a great player and I was prepared for her to play her best.
She then rose to a career-high mark of 38 in January 2015 before slipping down again. "But to do with myself, I'll keep everything the same, my routine, what I'm going to eat, sleep".