Andrea Pavan outlasted three-time Major winner Padraig Harrington in a thrilling battle on the final day to claim his first European Tour title at the D+D Real Czech Masters.
The duo entered round four at the Albatross Golf Resort tied for the lead, but Harrington looked set for his 16th European Tour victory when he opened up a three-shot lead at the turn.
Pavan, however, had other ideas as he carded a closing 67 in 31 to beat his Irish rival by two shots.
The Italian's 22-under total set a new record for the event and eclipsed Thomas Pieters' winning score in 2015 by two shots.
Malaysia's Gavin Green matched Harrington with a closing 69 to finish on 17 under, two shots clear of Scotland's Scott Jamieson and England's Lee Slattery.
Pavan won the Challenge Tour Rankings in 2013 after finishing runner-up in 2011 and now has a European Tour title to add to his four on that circuit.
He came through the qualifying school in November and enters the winner's circle in his 112th event, making it three Italian victories in 2018 after Francesco Molinari's triumphs at the BMW PGA Championship and Open Championship.
"It's unbelievable, it's massive," he said. "I've won four times on the Challenge Tour, but that was a long time ago. I'm going to enjoy this one because it's really hard to get and I'm just going to keep working on the things that seem to be working and enjoy the success.
"I'm going back home tomorrow and we're having a second baby, a little girl due on Wednesday. We're really excited about it and I can't wait to celebrate with my family.
Harrington found sand on the first tee and was forced to lay up, but he got up and down and holed out from about 15 feet to take the lead.
Pavan dropped a shot on the second and Harrington saved par from a ragged tee shot to take a two-shot lead.
The Ryder Cup vice-captain hit a bunker shot to two feet for another birdie on the sixth, while Pavan made his first gain of the day from eight feet to stay within two.
Harrington then made the most of the par-five ninth after laying up to extend his advantage to three with nine to play.
Pavan had missed a good chance at the ninth but the next two par fives were more pleasing, with an excellent bunker shot at the tenth and a smart approach to the twelfth reducing the gap to one.
Harrington responded in stunning fashion, almost making a hole-in-one at the par-three 13th to regain a cushion.
But Pavan was not to be outdone, hitting an approach to six feet for birdie on the 14th, and when Harrington bogeyed the next after getting into trouble off the tee, it was all square at the top.
The 29-year-old barely cleared the water off the tee at the par-three 16th, but rolled in a 25-footer from the fringe to take his first solo lead of the day with two to play.
A 15-foot putt at the 17th brought another birdie and a par on the last brought celebrations on the 18th green.
"Padraig has so much experience, such a great player and he played beautifully," added Pavan. "The putt on 16 was massive. It could have gone either way, he was ahead of me most of the day, but once I got ahead I stayed aggressive."
Green started with seven straight pars but a superb approach to the eighth sparked a hat-trick of birdies before he finished with another eight pars.
Slattery made five birdies and a single bogey in a 68, while Jamieson also had a dropped shot and three gains in a 70.
England's Tom Lewis moved into contention with six birdies in 13 holes, but found water on the 16th for a double-bogey to finish eight over.
Fiji International presented by Fiji Airways champion Gaganjeet Bhullar and South Africa's Jacques Kruyswijk finished on 13 under, one shot clear of a group of nine players including Ryder Cup hopefuls Eddie Pepperell and Thomas Pieters.
Full results can be found here