Thomas finished second in yesterday’s final mountain test, extending his lead over Tom Dumoulin to two minutes and five seconds ahead of today’s decisive time-trial.
LottoNL-Jumbo’s Primoz Roglic took the stage win in Laruns, 19 seconds ahead, to dislodge Thomas’s Sky team-mate Chris Froome from the podium on a day when the four-time Tour winner struggled to keep pace on the last climb.
But all eyes are now on the gap between Thomas and Dumoulin in anticipation of a rolling 31 kilometre time-trial which will set the final general classification order before tomorrow’s traditional procession into Paris.
“I hope I’ll be able to sleep,” said Thomas. “It was a big day and I’m happy to get that ticked off.”
Thomas has never been so close to such a major win in his road career, but the two-time Olympic team pursuit champion is no stranger to pressure.
“I guess it’s a bit like the Olympic final in London. That was big tension the day before but at least with this it’s kind of spread out.
“Obviously it comes down to Saturday. I think I can just take confidence with how I’ve been riding, recover as best as possible and what will be will be.”
This, Thomas said, is “squeaky bum time”. But though Dumoulin may be the world time-trial champion, all the signs so far in this Tour suggest Thomas has the legs to defend his advantage as long as he can avoid incident.
“I’m not taking anything for granted,” he said. “I just want to get out there and do the best ride I can. It’s nice to have that buffer. I don’t have to take any risks but I’ve still got to get through it.”
Yesterday was the stage that worried Team Sky more than anything – a 200.5 kilometres test from Lourdes that included over 5,000 metres of climbing and took on the Aspin, Tourmalet and Aubisque.
Thomas never broke as his rivals prodded and probed, but while he looked comfortable Froome was in danger of cracking on the final climb and it was as much as he could do to finish with Thomas and Dumoulin as Roglic cashed in.
The attacks started at the foot of the Tourmalet, with Movistar’s Mikel Landa and AG2R La Mondiale’s Romain Bardet the key players who leapt off the front of the peloton.
Sky looked unruffled but over the course of the Tourmalet’s 17km, at an average gradient of 7.3 per cent, Landa and Bardet were in a group that pulled more than two minutes clear.
When the advantage grew to over three minutes in the valley, Landa was 80 seconds off yellow in the virtual classification.
Cooperation in the lead group disintegrated as they made their way up the Aubisque, and attention turned to attacks from the yellow jersey group.
Roglic’s team-mate Steven Kruijswijk and then Dumoulin launched moves, looking to soften up Thomas without success.
“The main thing was to follow Tom,” Thomas said. “I was quite confident I was feeling good enough to follow him. I wasn’t super-stressed but obviously it was tough.”
While Thomas stuck to the wheels, Froome risked cracking on the final inclines, dropping 30 seconds back at one point. With his tongue hanging out and his legs spinning furiously, the apparently exhausted Froome needed to be paced back up by the outstanding 21-year-old Egan Bernal.
After cresting the Aubisque, a terrifying descent followed as they raced down the mountain in poor visibility.
It was in the mist that Roglic attacked, and the former junior world ski jump champion launched himself off the side of the mountain – though not in a fashion that impressed Dumoulin, who claimed Roglic had drafted off a camera bike to get away.
If Roglic did not exactly deny following a bike, he insisted it made no difference.
Julian Alaphilippe got himself in the day’s break to crest the Aspin first and wrap up the King of the Mountains competition, but not satisfied the Quick-Step Floors’ rider was first over the Tourmalet for good measure before dropping back.