Jeremy Chardy reached the round of 16 for the first time at the Australian Open with a fighting five-set win over sixth seed Juan Martin Del Potro on Saturday.
The 36th-ranked Frenchman raced to a two sets to love lead, before Del Potro pulled back to level the match only to prevail 6-3, 6-3, 6-7 (3/7), 3-6, 6-3 in 3hr 45min on Hisense Arena.
Chardy was ecstatic to have beaten the former US Open champion and will now face Italian 21st seed Andreas Seppi in an unexpected fourth round matchup on Monday.
Seppi upset Croatian 12th seed Marin Cilic in another five-setter.
"I beat (Andy) Murray last year in Cincinnati, but here it's something more because it's the Australian Open, third round, I play a top player," Chardy said.
"It's a big win for me. Maybe the best of my career. I'm so happy, I enjoyed it."
It is the second time 25-year-old Chardy has reached the fourth round at a Grand Slam after breaking through at the 2008 French Open. He had won only once in five previous trips to Melbourne.
His forehand was his big weapon with 44 winners along with 20 aces in his an overall total of 78 winners.
"I play slice with my backhand and I try to play short slice because he has to come off the baseline. Then I can go full power with my forehand," Chardy said of his tactics.
Del Potro, who was playing in his first official tournament of the year, has yet to win from two sets down.
"Jeremy played really well in the fifth set. He deserved to win the match. He broke my serve," Del Potro said.
"He was so calm to close out the match. The tournament for me is over now. I have to work hard because the season has just started.
"I believe in my game, myself. I will work very hard for the future."
The big Argentinian was under pressure from the outset with a service break in the second game and he staved off three set points at 3-5.
But the streaky Frenchman clinched the opening set on his fourth set point with a cracking forehand winner.
Del Potro was off colour and was broken again in the fifth game of the next set and was two set points down in the ninth game when he netted a forehand to go two sets behind.
He finally broke Chardy's service in the opening game of the third set only to give it back in the following game.
The sixth seed fought off four break points in the sixth game before taking the third set to a tiebreaker. He relished the chance and powered to the set on the back of two mini-breaks as Chardy began to look vulnerable.
Del Potro broke in the eighth game and served out to level the match in the fourth set.
But he gave Chardy his chance with a weak service game in the eighth game of the final set and was broken was he put a forehand wide.
Chardy served it out and sealed victory with an ace.