Tour de France: Wiggins repels 'Shark' attack as Sky live on their nerves during first Alpine stage Attacks by the 2011 Tour de France winner, Cadel Evans, and by the 2010 Tour of Spain champion, Vincenzo Nibali; attacks on the ascent of a 17 km Alpine climb by the Belgian top-10 challenger, Jurgen van den Broeck; attacks almost within sight of the finish, by Evans again: as Bradley Wiggins had warned during the rest day, as race leader, assuming he stays in yellow, there will be no respite for the Londoner until the Tour reaches Paris. "It's like junior racing, exciting stuff and good for the telly," Wiggins - who came through unscathed and with his lead intact - said with a half-ironic smile when asked about how it felt to be put under such pressure. By letting a huge break of 25 riders go away early, Sky had tried to lower the temperature on a stage featuring a viciously long Alpine climb, the Col du Gran Colombier, mid-race - "It's evil" was how Sean Yates, Sky's sports director, graphically recalled it from his own racing days - and several tricky, single-track descents on Tarmac melting gently in the warm, stormy weather. But to no avail. As the 25-strong move shrank to just four riders ahead on the Colombier's mixture of painfully steep ramps - finally culminating 40km later in a last-ditch attack and win for France's most popular rider, Thomas Voeckler - Sky attempted to keep Wiggins's overall contenders on the leash. Van den Broeck's three attempts to go clear on a seemingly endless series of hairpin bends and short straightaways snaking through dense woodland were quickly contained, but after Evans tested the water at the summit of the Colombier, Nibali, currently fourth overall, then made an even more prolonged effort on the twisting, narrow descent, and went clear. The rider nicknamed the "Shark of Messina" is well known as a demon descender and Wiggins said later that his coldblooded downhill charge away at speeds of over 90 kmh had been expected. But it did a great deal of initial damage nonetheless - particularly when, after linking up with team-mate Peter Sagan, a triple-stage winner in the first week who was again in the break of 25, the burly Slovak helped Nibali raise his advantage on Wiggins's chasing group to over a minute. Matters were not simplified for Sky when Wiggins's team-mate Michael Rogers punctured at the top of the Colombier, suffering a two minute delay that meant he was unable to assist Sky in pursuit of Nibali. Aware that Wiggins was in need of much support as he could get, when Rogers finally reached the finish the air was as blue as the Sky team-bus as the former triple world time-trial champion vented his frustration. Fortunately, Nibali's move imploded as Sagan cracked, and Sky upped the pace further on the shallow but steady third category ascent of the Col de Richemond to reel in their slippery Italian rival. However, another late attack, almost within sight of the finish, by Evans kept Wiggins on his toes, and although he seemed relatively unpeturbed about Nibali's attack, the Italian's bold move and Evans's repeated digs confirmed Wiggins will not be able to rest on his laurels. It went to script; I wasn't too worried. I knew that Nibali would have had to make a major effort to stay away, and there was a fair bit of flat afterwards to pull him back," Wiggins, 13th on the stage, said later. But you can't underestimate anyone in the top 10: Nibali won the Tour of Spain in 2010 and has been third in the Tour of Italy, and there are lots of dangerous rivals.  Off the bike, the pressure is lower, but only just. Sky woke up to questions raised about their employing a doctor (not on the Tour) who had previously been part of Dutch outfit Rabobank when they was embroiled in a doping scandal in 2007. And after the stage, Wiggins launched his second diatribe about his credibility as a Tour leader in the space of four days. Asked if he understood why he was questioned on the subject of doping given that a French rider, Remy di Gregorio, had been taken into custody as part of a police investigation into banned drugs the previous day, Wiggins gave an answer lasting nearly three minutes: "I'm not some **** rider who's come from nowhere, I've been six times world champion, triple Olympic champion, fourth in the Tour de France, third in the Vuelta." Wiggins singled out, once again, anonymous Twitter trolls who insinuate it is impossible to win the Tour without doping. He said: "I just don't feel like I have to sit here and justify myself to everyone. To me, it's them *******all over everything I've done, by just saying, 'Oh yes, he's cheating' or whatever. That's what really gets to me. After yesterday's incursion into the Jura, today features a far more difficult challenge, the 19km La Toussuire Alpine climb, the last of three major cols in what Wiggins considers "the most difficult single stage of the 2012 Tour de France." And if yesterday's stage made for spectacular TV viewing, as Wiggins put it, today's should be even more gripping. Come what may, Wiggins will today ride into the history books as the Briton who has now led the Tour de France for the longest period of time: four days - one more than Chris Boardman in 1994 after he won the Lille prologue - and Scot David Millar, who also held the lead for three days after winning at Futuroscope. And if that represents one major landmark, in today's Alpine challenge a large part of the jigsaw en route to his becoming Britain's first Tour winner could fall into place, too.