Gauff, who is yet to drop a set at Flushing Meadows this year, will play France's 17th seed Caroline Garcia in the next round.

"It feels insane," said the 18-year-old. "Ashe Stadium chanting my name, I was trying not to smile."

Speaking to Amazon Prime, she said: "It was really physical, it felt like a three-setter.

"I really think my mentality helped me today.

"I'm so happy, being in my home Slam and finally getting to a quarter-final. This tournament has always been special for me, growing up watching it. I'm just so excited to continue to play and experience this atmosphere."

Like Gauff, this is the furthest Garcia has progressed in New York, after she comfortably defeated American Alison Riske-Amritraj 6-4 6-1.

It is only the second time Garcia - now unbeaten in her past 10 singles matches - has reached the last eight at a Grand Slam, previously doing so on the clay of Roland Garros in 2017.

Facing Zhang for the second time, having beaten her in Miami earlier this year, Gauff conceded the break in her first service game, but broke back immediately to cancel out her opponent's advantage.

The pair again exchanged breaks later in the opening set, with Gauff again breaking Zhang's serve in the penultimate game before serving out the set.

As the rain started to fall and the stadium roof was closed, Gauff made a nervy start to the second set, facing a break point before recovering to avert the danger.

In the fifth game, Zhang was forced to save two break points herself before breaking in the eighth, with Gauff throwing in regular double faults.

But it was from that point that Gauff started to assert control. After Zhang missed a set point, the American reeled off four straight games, saving a break point along the way.

On facing Garcia next, Gauff said: "She's obviously been playing really good tennis, I've been playing well too so I think it's going to be a great match.

"No matter what, win or lose, I know I'm going to give it my all."

A first US Open quarter-final also awaits Ajla Tomljanovic, who showed no let-down from ending Serena Williams' career on Friday.

The Australian defeated Russian Ludmilla Samsonova 7-6 (10-8) 6-1.

From 4-1 down in the first set, Tomljanovic battled back to 5-4 before an astonishing 18-minute game in which she saved seven set points on her way to holding serve.

After winning the tie-break, she then cruised through the second set to book a last-eight spot, where she will take on Ons Jabeur of Tunisia, who beat Russian 18th-seed Veronika Kudermetova 7-6 (7-1) 6-4.

It will be Jabeur's first appearance in the quarter-finals of the US Open.

The Wimbledon runner-up fought back from 5-2 down in the opening set and after drawing level at 5-5, she dominated the tiebreaker.

Serving for the match, Jabeur was broken by Kudermetova but the world number five closed out the set when she disrupted the Russian's serve in the next game.

On facing Tomljanovic in the last eight, Jabeur said on her on-court interview: "Ajla plays really well and I know it's going to be a physical match. She's going to hit really hard, so I have to be ready physically."