David Ravetto won his first DP World Tour title with a stunning closing 64, while closest challenger Jesper Svensson fell on the 16th hole of the D+D REAL Czech Masters.
Lavitto, 27, led with six birdies on the front nine in Prague on Sunday, turning an overnight one-shot deficit behind Svensson into a three-shot victory.
Swenson came back with a birdie on the 10th hole and when Lavitto bogeyed the 12th hole, Swenson was one shot away, and the two made birdies on the 13th and 15th holes before the crucial moment came.
Swenson had trouble hitting his tee shot on the 16th hole for the second straight day, but in stark contrast to his amazing rescue performance on Saturday, when he hit a 3-wood 311 yards to the center of the fairway, this time it took him four shots to reach the green and then three-putted.
Lavitto pushed his approach from just in front of the green for birdie, moving to 23 under and taking a four-shot lead, which he has maintained ever since.
He said: “I felt good all week and we had a strategy to just go and have fun and it worked well. Of course, I had some stress and my hands were shaking but that's what you practice for.
“After I drove down the middle of the fairway and walked up to the 18th hole, I was so emotional that I almost broke down and started crying on the fairway. When I saw my caddie and my girlfriend, I couldn’t hold it in any longer.
“I'm sure we'll celebrate – we're French, we know how to do it! Something could happen tonight in Prague and maybe next week in Paris.”
Scotland's Richie Ramsay tied for third at 18 under with fellow Ravetto players Adrien Saddier and Frederic Lacroix.
British trio Brandon Robinson Thompson, Alex Fitzpatrick and Paul Waring tied for sixth with Austrian Bernd Wiesberger at 16 under.
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