MELBOURNE, Australia (AP) -- Still smiling an hour later, France's Jeremy Chardy said he had just played "the most beautiful match" of his career.
The 25-year-old Frenchman staged the biggest upset so far at the Australian Open, beating No. 6 Juan Martin del Potro in a five-setter that lasted nearly four hours Saturday.
"I feel so much emotion," Chardy said after the 6-3, 6-3, 6-7 (3), 3-6, 6-3 win. "It's a great moment for me. Everyone dreams of this."
Chardy, who lost in the first round last year, frustrated del Potro with a tricky slice and a mix of drop shots, volleys and an inside-out forehand. One fast-paced rally in the third set sent the 6-foot-6 Argentine sprinting into the stands and hurdling a barricade.
Del Potro, the 2009 U.S. Open champion, was seen as a potential challenger to the Big Three: No. 1 Novak Djokovic, No. 2 Roger Federer, No. 3 Andy Murray. In his first two matches, del Potro had dropped only 13 games -- the fewest among all men in the draw.
But it was Chardy who dominated with 78 winners, including 44 on his forehand side. The big-hitting Del Potro had only 12 forehand winners in five sets.
"The match was really tough," said del Potro, who rallied from two sets down to level the match but dropped his serve in the crucial eighth game of the final set. "In the end when he had the chance to break me, he did. I think that was key," said del Potro.
"Jeremy played so strong for four hours," del Potro added. "He serves well. He made a lot of winners with the forehand, very good slices."
Chardy reached the fourth round of a major once before -- five years ago at Roland Garros.
"I played some tennis I never would have thought I was capable of playing," the No. 36-ranked Chardy said. "Five sets, to be here in a Grand Slam. It's the most beautiful match of my career."
He's one of four French players to reach the fourth round, matching the country's record at Melbourne Park.
Seventh-seeded Jo-Wilfried Tsonga and No. 9 Richard Gasquet also won their third-round matches Saturday, while No. 14 Gilles Simon was playing Gael Monfils later Saturday for a spot in the next round.
Asked if a Frenchman could possibly win the Australian Open, Chardy smiled broadly.
"Maybe me!" he said.
IN PRAISE OF GUSSIE: Serena Williams paid tribute to Gussie Moran, the trailblazing tennis star who scandalized Wimbledon in 1949 by wearing a tennis skirt above her knees and lace-trimmed underwear.
Moran died at age 89 on Wednesday in Los Angeles.
Williams, the 15-time Grand Slam winner, who has a flair for on-court fashion, said it was women like Moran who paved the way for how female athletes can dress today.
"When you look at the history of tennis, especially Wimbledon, you see these women wear these long gowns," said No. 3-seeded Williams, gesturing toward her feet. "I don't know how they could have possibly played in that."
As a 25-year-old seeded seventh at Wimbledon in 1949, Moran made jaws drop and flashbulbs pop when she showed up for her first match minus the knee-length skirt considered proper for women at the time. She lost the match, but her striking fashion statement appeared on magazine covers around the world. The British press dubbed her "Gorgeous Gussie."
Once ranked as high as fourth in the United States, Moran never achieved great fame for her tennis.
Perhaps in a sign of how far tennis fashion has developed, No. 1 Victoria Azarenka of Belarus said she had never heard of Moran. And Williams said she knew "the name Gussie" but needed a reminder about her legacy.
"Someone always has to be first. I think that obviously she made a way for not only tennis players but just women in general in sport," Williams said. "Like you don't have to wear a dress to your ankles to be a female athlete playing sports.
"I think being a trailblazer is honorable."
BACK PAIN: In one of those "I'll have what she's having" moments, No. 1 Victoria Azarenka quipped she wished she had a back problem.
At times during her third-round match, Azarenka looked like the underdog as the relatively unknown 23-year-old American Jamie Hampton pounded forehands and had the crowd on center court cheering, "C'mon, Jamie!"
Azarenka overcame the scare to win 6-4, 4-6, 6-2.
Playing with her lower back heavily taped, Hampton said she began feeling pain late in the first set. She took a medical timeout before serving out the second set.