The unseeded Slovak defeated American wildcard Alison Riske 6-3 5-7 6-2 on Monday to end an extended absence from the last eight at Flushing Meadows since her loss to Serena Williams in 2002 as a 19-year-old.
In a commendable if not spectacular career, Hantuchova has since reached the world number five ranking, won the Fed Cup, secured the career grand slam in mixed doubles and made the semi-finals of the 2008 Australian Open. And now, having fallen to number 48 in the world, Hantuchova is back where it all started.
"It means a lot to me because I love New York," she said. "I could live here in one second. I just love the city, it's got so much energy, atmosphere. It's the last grand slam of the year and obviously you always want to finish on a high.
"The tournament is only starting now for me. It just means the world to me to again be in the quarter-finals."
Hantuchova will meet either Belarus' second seeded Victoria Azarenka or 13th-seeded Ana Ivanovic of Serbia for a place in the semi-finals.
She said there was a simple reason why players over 30, including Serena Williams and Australian veteran Lleyton Hewitt, were faring well in the men's and women's events at Flushing Meadows.
"Just the love for the game," she said.
"I love doing what I'm doing so much that I wouldn't change it for anything else in the world. That's the reason I'm here.
"I just appreciate everything a lot more. I appreciate being able to be a tennis player, to be healthy, doing what I'm doing. It's a big privilege to be in this position, to be so lucky in my life."
She saw the irony in being regarded as old in tennis but young in day-to-day life.
"We always feel so much older in the tennis world than we do in the normal life," she said. "I'm so happy there's so many girls of my age, and older, still around. I think we keep pushing each other. It's great for our generation.
"We've been through so much, we know exactly what to do. Sometimes we don't do it, but we know what we should be doing."
Hantuchova's claim to fame in the early stages of the US Open was partnering with Martina Hingis in the women's doubles.
They were beaten in the first round by top-seeded Italians Sara Errani and Roberta Vinci.
"It's always great to have someone like that around," Hantuchova said. "She understands the game so much. Once you are a champion, you will always be a champion."