L'Alpe D'Huez - Christophe Riblon became the first Frenchman to win a Tour de France stage this year and Chris Froome boosted his overall lead despite a late struggle on Thursday's 18th stage.Riblon caught American Tejay van Garderen with about 2km remaining on the day's second ride up L'Alpe d'Huez, one of the Tour's most famed climbs.Riblon threw his hands up and pumped his fists after clinching the second Tour stage win of his career, three years after winning another mountain trek. Van Garderen finished 59 seconds behind in second, and Italian Moreno Moser was 1:27 behind in third."To raise my arms aloft at L'Alpe d'Huez is incredible," Riblon said. "With 5km to go I thought I had lost it."He dedicated the win to his AG2R La Mondiale teammate Jean-Christophe Peraud, who fractured his shoulder in Wednesday's time trial and had to pull out."We wanted to end this bad spell," Riblon said.Froome, 3:18 back in seventh, extended his comfortable lead over his main rival Alberto Contador to more than five minutes with just three stages remaining. He is edging closer to becoming the second British rider to win the Tour, following Sky teammate Bradley Wiggins' success last year.The 172.5km route from Gap to L'Alpe d'Huez featured two HC ascents of L'Alpe d'Huez — meaning they were so tough they were beyond classification, known as Hors Categorie."It wasn't easy," Froome said. "The whole team worked very hard to keep the yellow jersey."Contador was dropped by Froome on the second ascent of L'Alpe d'Huez and finished 11th. The two-time former champion just held on to second place overall, but 5:11 behind Froome.Colombian climber Nairo Quintana moved up to third overall and 21 seconds behind Contador.With about 12km to go on the last climb, Froome launched one of his trademark attacks. About a kilometre later, he attacked again and only Quintana could keep up with him as Contador dropped away.But then Froome called for assistance with about 4km to go with what looked to be bike trouble. No team car could get up to help him due to the thousands of fans in the way. So, instead teammate Richie Porte gave him what looked like an energy bar to eat."I asked for some sugar," Froome said. "Going twice up L'Alpe d'Huez is difficult."Froome was handed a 20-second penalty for illegal feeding as a result. Porte was also penalised 20 seconds. Van Garderen and Riblon were part of a nine-man breakaway."This is a reward for me," Riblon said. "It's the fourth time I've been in a breakaway on this race."They were chased by two riders from Contador's Saxo-Tinkoff team, Nicolas Roche and Sergio Paulinho, as they tried to increase the pressure on Froome's Sky teammates. Roche dropped off as they approached the first big ascent of the day.Like players in a card game, Froome and Contador waited for the other one to show his hand. But neither did at first.Van Garderen and Riblon reached the top of the next climb together, the Col de Sarenne, and braced themselves for a long and razor-thin descent.In recent days, Froome had expressed concerns that the Sarenne descent, with its bumpy, pockmarked surface, was too dangerous. Riblon went off the road, and luckily for him he rolled onto a grass bank and not over the mountain."I have a lucky star over me," Riblon said.Two days ago, Froome also criticized Contador for riding too aggressively on a sharp descent to Gap, almost causing the Briton to crash.But Contador attacked Froome almost immediately down Sarenne, passing him on the outside like a Formula One driver.Contador, joined by his teammate Roman Kreuziger, opened up a gap of about 20 seconds but lost that advantage after a few minutes. Contador's bad day was compounded when he had to change bikes.Fans jammed the 21 hairpin bends on L'Alpe d'Huez in a chaotic atmosphere. Many were in fancy dress: Vicars, super heroes, and other outfits of more dubious taste.But there was still a degree of organization within the mayhem, with certain corners reserved for fans from certain countries.One of those is known as "Dutch Corner" and several hundred screaming, shouting Dutch men and women formed a vortex that sucked the riders in amid a surreal cacophony of indecipherable shrieks, howls, and wails.Several dozen Norwegians, some in plastic Viking helmets, formed a human shield around one corner near the top. Elsewhere, a dozen or so Colombians marched uphill carrying a giant national flag.Camping cars lined the hill; there were British Union Jack flags everywhere, Irish tricolours, Australian fans dressed in kangaroo suits, and others dressed as inflatable giant flowers.Now and again, a distressed-looking police officer would blow a whistle, trying to stop fans from getting too close.One got too close to Riblon, who elbowed him in the chest, and a young boy ran in front of Froome, who just about avoided him.Barricades were erected on the last part of the climb to give the riders some respite.Results of the 18th stage of the Tour de France, a 172.5km ride from Gap to L'Alpe-d'Huez on Thursday:1. Christophe Riblon (FRA/ALM) 4hr 51min 32sec2. Tejay Van Garderen (USA/BMC) at 0:59s3. Moreno Moser (ITA/CAN) 1:27.4. Nairo Quintana (COL/MOV) 2:12.5. Joaquin Rodriguez (ESP/KAT) 2:15.6. Richie Porte (AUS/SKY) 3:18.7. Chris Froome (GBR/SKY) 3:18.8. Alejandro Valverde (ESP/MOV) 3:22.9. Mikel Nieve (ESP/EUS) 4:15.10. Jakob Diemer Fuglsang (DEN/AST) 4:15.11. Alberto Contador (ESP/SAX) 4:15.12. Roman Kreuziger (CZE/SAX) 4:31.13. Michael Rogers (AUS/SAX) 4:45.14. Andrew Talansky (USA/GRM) 4:49.15. Jos Serpa Perez (COL/LAM) 5:18.16. Romain Bardet (FRA/ALM) 5:40.17. Igor Anton (ESP/EUS) 5:40.18. John Gadret (FRA/ALM) 5:42.19. Alessandro De Marchi (ITA/CAN) 5:47.20. Bart De Clercq (BEL/LTB) 5:56.129. Daryl Impey (RSA/ORI) 30:03.Overall General Classification (before 20sec time penalty to Chris Froome and Richie Porte):1. Chris Froome (GBR/SKY) 71hr 02min 19sec2. Alberto Contador (ESP/SAX) at 5:11s3. Nairo Quintana (COL/MOV) 5:32.4. Roman Kreuziger (CZE/SAX) 5:44.5. Joaquin Rodriguez (ESP/KAT) 5:58.6. Bauke Mollema (NED/BKN) 8:58.7. Jakob Diemer Fuglsang (DEN/AST) 9:33.8. Michael Rogers (AUS/SAX) 14:26.9. Michal Kwiatkowski (POL/OPQ) 14:38.10. Laurens ten Dam (NED/BKN) 14:39.11. Alejandro Valverde (ESP/MOV) 14:56.12. Andrew Talansky (USA/GRM) 16:24.13. Daniel Navarro (ESP/COF) 19:18.14. Maxime Monfort (BEL/RSH) 19:56.15. Mikel Nieve (ESP/EUS) 24:13.16. Daniel Moreno (ESP/KAT) 30:05.17. Romain Bardet (FRA/ALM) 30:45.18. Andy Schleck (LUX/RSH) 31:19.19. Daniel Martin (IRL/GRM) 34:22.20. Richie Porte (AUS/SKY) 37:42.67. Daryl Impey (RSA/ORI) 1h50:54.