Thomas De Gendt (Vacansoleil-DCM) celebrates his win. (Image credit: Isabelle Duchesne)

Paris-Nice leader Thomas De Gendt scored the biggest victory of his career Sunday when he held off the charging herd of sprinters coming to the line on the heels of his successful breakaway in Houdan.

The 24-year-old Belgian topped Frenchman Jérémy Roy (FDJ) from the move, while the pair's erstwhile companion Jens Voigt (Leopard Trek) was caught by the bunch as Heinrich Haussler (Garmin-Cervélo) took the field sprint for third.

De Gendt, whose last victory came in the 2009 Tour de Wallonie, revealed the secret of his 2011 success, which began with a second place on a stage of the Tour Down Under: giving up his favourite foods to shed four kilograms in the six weeks since the Australian race.

"I'm also three kilos lighter than last year," said De Gendt, who transferred from Topsport-Vlaanderen to Vacansoleil during the off-season. "Salami and sausages are my weakness. I love to eat everything that a pro cyclist shouldn't eat."

His teammate Romain Feillu was one of the riders the most expected to strike on stage 1 at Paris-Nice, but the Frenchman was ninth on the finishing line in Houdan today. He was delighted for De Gendt, who delivered Vacansoleil its first World Tour win.

"Thomas has an enormous potential," Feillu told Cyclingnews on the finishing line. "He knows how to hurt himself. He can time trial pretty well. At the Santos Tour Down Under, he was already close to win stage 4. He was amazing in Australia because he was already able to climb although he was a bit overweight."

De Gendt had options to join the two super teams from his country but opted for Dutch outfit Vacansoleil rather than Omega Pharma-Lotto or Quick Step. "I had a better feeling with Vacansoleil," he said. He was recommended by Björn Leukemans who was impressed by him when he rode hard to win the hot spot sprints at the Tour of Burgos.

"I'm an attacker," De Gendt defined himself. "I ride my bike like crazy but I love that. I never preserve myself. I'm a little bit of a sprinter, a little bit of a time triallist and a little bit of a climber, but I don't excel in anything really."

For seven years, the teenager who started cycling on a BMX bike with road handlebars at the age of 4 followed the courses of the cycling school of Ronse near his home of Semmerzake in the heart of the Flemish Ardennes. Former Panasonic rider Eric van Lancker was his teacher but he admits he wasn't very good at learning subjects other than cycling. "It was more difficult for me to learn French than to win today," he said.

De Gendt was delighted to win one of the famous stuffed lions for his girlfriend Evelyn. The Credit Lyonnaise mascot came along with the yellow jersey of Paris-Nice.

"It makes my 2011 season successful already, but this is not the end," he commented. "There are another 80 days of racing to come. I've asked Vacansoleil to give me the chance to ride the Ardennes classics because I feel better in the hills than on the cobblestones and in the wind near my place. We have Leukemans and Stijn Devolder for the Flemish classics."

Feillu took one second bonus during stage 1 of Paris-Nice in order to get his team a better position in the convoy for stage 2 where echelons are expected. "This is useless now after Thomas' win," he laughed. "Now I might try and win tomorrow in Amilly."

The Frenchman seemed relieved after Vacansoleil sacked Riccardo Ricco. Two months ago, he had commented that he wasn't exactly happy to be the Italian's teammate. "The past three weeks have been difficult for our team but today, we can look at the future positively," said team manager Daan Luijkx. Vacansoleil awaits Monday's decision of RCS Sport to welcome them at the Giro d'Italia or not after the latest Ricco affair.