As he crossed the finishing line he beat his chest and let out a cry of delight – knowing the Tour was his – before hugging his wife Sara and Team Sky principal Sir Dave Brailsford. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Thomas, wearing the overall leader’s yellow jersey, rides during the 20th stage of the 105th edition of the Tour de France Credit: MARCO BERTORELLO/AFP Steve Williams, his former PE teacher at Whitchurch High School – which remarkably also produced the Real Madrid star Gareth Bale and the former Welsh international rugby player Sam Warburton – told The Sunday Telegraph: “Ultimately, Geraint is a baseline bloke. He kept his feet on the floor, and he hasn’t forgotten where he came from.”Back home they reckon Thomas will be more than able to handle the prospect of the fame and glory that victory in the Tour will bring.”I think that sort of character – who has a lot of inner strength – will be coping pretty well,” said Mr Williams. “He’ll be a very sad man when he has to come off his bike, because that’s what he loves doing.” Thomas hugs his wife Sara after completing Stage 20 of the Tour de France before Sunday’s procession through ParisCredit:Justin Setterfield/Getty Images In the Cardiff suburb of Birchgrove he is remembered as someone who has not forgotten his roots.It was typical of Thomas that mid way through the Tour he took time to send a video message to the sick 14-year-old daughter of Debbie Wharton, the coach who trained him at the Maindy Flyers velodrome in the early 1990s, telling her to “keep fighting”. When Geraint Thomas rides into Paris on Sunday, resplendent in the yellow jersey worn by the leader of the Tour de France, there will be a corner of the United Kingdom where the cheers will be particularly loud.Barring disaster during what is traditionally a processional route through the French capital, the 32-year-old will step onto the winner’s podium, making him the first Welshman to win what is arguably sport’s toughest endurance event and with it one of the most successful Welsh sportsmen of all time.Not only that, but he will be only the third Briton to win the Tour, after Bradley Wiggins and Chris Froome, since the near-three-week-long race began more than a century ago.That historic achievement will find its most enthusiastic supporters in Cardiff, where Thomas was born and went to school, attending a local comprehensive and cutting his competitive teeth at his nearby cycling club – the Maindy Flyers.From there he went on to become three times world champion and two time Olympic gold medallist.To described him as a local boy made good is therefore something of an understatement.Thomas all but ensured his win in Paris by maintaining an overall lead of 1 min 51 secs over his nearest rival Tom Demoulin after Saturday’s hilly 31 kms time trial through the Basque country. “The last time I cried was when I got married and I don’t know what’s happened to me.”In fact it was not supposed to be at all like this.At the start of the Tour Chris Froome, the defending champion, was Team Sky’s designated leader and it was Thomas’s job to ride in support of him, helping guide him to a 5th victory.But at key points in the high Alps Froome cracked and Thomas proved himself to be the stronger rider over the 3,351 kms of the Tour. Wiping away tears Thomas said: “I can’t believe it. I’m welling up. I don’t know what to say. It is just overwhelming. I didn’t think about it all race and suddenly I won the Tour.“It’s just overwhelming. I can’t speak man. It’s just incredible. I believed I could beat the guys here but to do it on the biggest stage of all over three weeks, it’s insane.