Bidding to become the first Australian woman to make the quarter-finals at the All England Club since Jelena Dokic 19 years ago, Barty fell 3-6 6-2 6-3 in a fourth-round nailbiter on Monday.

Unseeded Riske withstood 12 aces from Barty to chalk up her tour-best 14th grasscourt victory of the season.

The Court 2 boilover also ended Barty's 15-match winning streak and scuppered the 23-year-old's hopes of completing a rare French Open-Wimbledon title double.

"I'm so excited. Ultimately I'm so proud of myself how I handled today's match," Riske said after notching her first-ever win over a world No.1 and reaching her maiden grand slam quarter-final.

"I had to play aggressive and take it to Ash and that's what I did today.

"I couldn't be more proud of myself. I couldn't say what this means to me.

"Obviously getting to the quarter-finals is amazing but just the way I've been fighting is the most exciting for me."

An upset looked remote when Barty fired down four aces to start the match before taking the opening set in 32 minutes.

Riske was unfazed, calmly working her way into the contest with some fearless hitting from the baseline.

Piling the pressure on Barty with sustained attack and measured forays to the net, Riske broke Barty twice to seize the second set to make a fool of her ranking of No.55 in the world.

Staving off a break point in the fourth game of the deciding set, Riske nabbed another crucial break with a massive forehand winner to surge ahead 5-3, before retaining her poise to clinch a shock victory after one hour and 37 minutes.

"It really brings out the best in me," Riske said of her phenomenal run on grass over the past month.

"My game is very well suited to it," the 29-year-old said.

"I hit a flat ball and love coming to the net and I feel at home here. I love being at Wimbledon.

"It's just so special."

The American's maiden quarter-final will likely come against 23-times grand slam champion and seven-times Wimbledon winner Serena Williams, who plays Spanish veteran Carla Suarez Navarro later on Monday.

"Bring it on," Riske said.

Australian Associated Press