“Nicolette started very well while I was struggling to see the ball. I only had 20 minutes in the morning to train on this glass court and it took me a while (to get going),” said Wee Wern, who will be making her second successive US Open quarter-final appearance.
“But I’m happy to win the crucial first set ... and with the way I closed off the match in the fourth.
“It will always be an uphill task against Nicol as she is the world No. 1. But I’ve been playing well lately and I’m looking forward to challenging her again.”
Wee Wern lost in four sets to Nicol in the Asian Games final last month.
And Nicol knows it could be just as tough this time.
“It will be difficult against Wee Wern in the quarter-finals. But it’s great for Malaysia to see her move up the rankings,” said Nicol.
“Still, it’s the quarter-finals of the US Open and I’ll be focused.”
In other results, fifth seed Alison Waters of England was pushed to the limit before securing a 12-10, 11-8, 1-11, 15-17, 11-2 win over 16-year-old Egyptian Nouran Gohar.
Waters will meet another Egyptian – world No. 3 Raneem El Welily – in the quarter-finals.