The third seed, who received a bye in the first round, beat the American wildcard 6-3 6-1 in just over an hour.
Konta, the world number 18, hit 11 aces on her way to a comfortable victory.
The 25-year-old will play China's Saisai Zheng, who beat Alize Cornet in her second-round match, in the last eight on Friday.

Santner, 24, broke his finger in only his second game for the county in 2016.
"There is some unfinished business with Mitch," director of cricket Steve Rhodes told Worcestershire's website.
"Last summer he was very unlucky. Losing Mitch was a massive blow to our hopes of qualifying. We'd had a good start and him playing all those games would have been an extra bonus for us."
The left-arm batsman and spinner, who made his Test debut in 2015, will rejoin the Rapids following June's ICC Trophy in England.
Santner added: "I really enjoyed my time at Worcester with a great bunch of lads and it was so frustrating for me to pick up that injury in the very first T20 game.
"It's fantastic that I've got the chance to come back again next summer and hopefully I can make up for lost time and make an impact with bat and ball."
In August, Worcestershire signed Australia pace bowler John Hastings as their main overseas player for the 2017 season across all formats of the game.

The Queen's Park Rangers player made his NI debut in March and scored in his second game against Slovenia.
Washington, a postman just four years ago, followed that up with another goal against Belarus on Saturday.
"The last few months have been a crazy time and I don't think it has sunk in yet. I know I have been fortunate," said the 24-year-old.
"Football can be about being in the right place at the right time, and I have been lucky.
"Maybe in a couple of years I will look back and realise how mad it has all been."
Washington  combined representing non-League St Ives between 2010 and 2012 with a job delivering mail.
Having averaged more than a goal-a-game in his 50 appearances for a club in the ninth tier, he then got his break with Newport who paid £5,000 for him.
The Welsh club were promoted to the Football League in his first season, although Washington barely featured.
He then moved to Peterborough in 2014 and by mid-January of this year, when QPR took him from London Road, Washington had scored 15 goals and aroused the interest of Northern Ireland manager Michael O'Neill.
Washington had only been to the country once before his international bow against Wales in March but he qualified through the grandparent rule.
"It was nice to be accepted so quickly and so readily with Northern Ireland," he added.
"Life doesn't get much better. I'm proud of my achievements and just have to try to enjoy it."
British number one Johanna Konta reached the quarter-finals of the Bank of the West Classic in Stanford with a straight-set win over Julia Boserup.
[NEXT_CONCEPT]
Worcestershire have re-signed New Zealand all-rounder Mitchell Santner for the 2017 T20 Blast competition.
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Northern Ireland striker Conor Washington counts himself a lucky man as he prepares to head to Euro 2016.