Welshman Geraint Thomas is set to win the Tour de France for the first time despite losing the stage 20 time trial to his biggest rival.

Sunweb’s Tom Dumoulin beat four-time Tour winner Chris Froome by one second in the 31km time trial, with Thomas a further 13 seconds adrift.

But Thomas adopted a cautious approach and still holds a healthy lead of one minute and 51 seconds over Dumoulin, virtually assuring him of victory.

Protocol dictates that there are no changes to the standings in Sunday’s final race, meaning that all Thomas has to do to officially claim Tour de France victory is finish the race.

And he will enter the procession on top of the world after a brilliant race in which he has upstaged Sky teammate and defending champion Froome.

“It’s insane,” Thomas told ITV.

“Tour de France! I can’t believe it. I’m really trying not to cry. It’s unbelievable.

“I tried not to think about it [victory], just take it day by day. I’ve won the Tour de France, man … I don’t know what to say.”

Thomas continues Team Sky’s dominance of the famous race in recent years.

Bradley Wiggins won the Tour for Sky In 2012, before Froome saluted in 2013, 2015, 2016 and 2017.

Froome moved ahead of LottoNL-Jumbo’s Primoz Roglic and into third position in the time trial, meaning Team Sky will fill two of the three podium spots.

Froome is two minutes and 24 seconds behind Thomas in the general classification standings.

For Dumoulin, victory in the time trial was bittersweet.

The world time trial champion, who finished second to Froome at the Giro d’Italia earlier this year, said he was proud of his achievement.

“Being second in the Tour de France is already an achievement in my eyes,” he said.

“But of course, I’d like to go for a win one day.

Dumoulin celebrates his stage victory. Photo: Getty

“No one expected me to do so well, including myself, in this Tour de France.

“We also didn’t have an eye on the podium, we were just going for it … we have to look at doing better in the next years.”

Dumoulin also flagged that he will not compete in both the Giro and the Tour in 2019, a sign he and his team will target victory in France above anything else.

The stage

With riders setting off one by one and the race’s top contenders going later in the day, Aussie Michael Hepburn took the chance to create some headlines.

The Mitchelton-Scott rider set the quickest time so far, a strong 42 minutes and 15 seconds, and it stood for some time.

It was eventually overtaken, though, as all eyes turned to Froome who burst out of the blocks and put pressure on Roglic and Dumoulin.

That forced Dumoulin into action and Thomas also begun quickly, before a minor wobble on a corner forced a re-think.

“When I had a wobble on that corner I thought, ‘chill out a bit’,” Thomas said.

“Nico [Team Sky sporting director Nico Portal] was on the radio and told me to make sure I win the Tour, don’t risk anything.

“I didn’t think the course was too technical but then every corner seemed like a 180 degree turn.

“I felt good and started putting the power down but then took every corner super slow. I can finally let the emotion come.”

Thomas eased off, allowing Dumoulin and Froome to battle for glory and the former’s time was eventually the strongest.

But it mattered little in the scheme of things as Thomas and Team Sky started to celebrate a famous victory.

Stage 20 results

1. Tom Dumoulin (Sunweb) 40 mins 52 secs
2. Chris Froome (Team Sky) + 1 sec
3. Geraint Thomas (Team Sky) + 14 secs
4. Michal Kwiatkowski (Team Sky) + 50 secs
5. Soren Kragh Andersen (Sunweb) + 51 secs
6. Bob Jungels (Quick-Step Floors) + 52 secs
7. Ilnur Zakarin (Katusha-Alpecin) + 1 min 2 secs
8. Primoz Roglic (LottoNL-Jumbo) + 1 min 12 secs
9. Marc Soler (Movistar) + 1 min 22 secs
10. Michael Hepburn (Mitchelton-Scott) + 1 min 23 secs

General classification standings

1. Geraint Thomas (Team Sky) 80 hrs 30 mins 37 secs
2. Tom Dumoulin (Sunweb) + 1 min 51 secs
3. Chris Froome (Team Sky) + 2 mins 24 secs
4. Primoz Roglic (Team LottoNL-Jumbo) + 3 mins 22 secs
5. Steven Kruijswijk (Lotto NL-Jumbo) + 6 mins 8 secs
6. Romain Bardet (AG2R La Mondiale) + 6 mins 57 secs
7. Mikel Landa (Movistar) + 7 mins 37 secs
8. Daniel Martin (UAE Team Emirates) + 9 mins 5 secs
9. Ilnur Zakarin (Katusha-Alpecin) + 12 mins 37 secs
10. Nairo Quintana (Movistar) + 14 mins 18 secs