ESPELETTE, France -- No longer merely a support rider for Chris Froome, Geraint Thomas is going to Paris in the yellow jersey. The Welshman with Team Sky effectively sealed his first Tour de France title by protecting his lead in the time trial on the penultimate stage on Saturday.

Thomas takes an advantage of 1 minute, 51 seconds over Tom Dumoulin into the mostly ceremonial finish on the Champs-Elysees on Sunday.

"It's just overwhelming," Thomas said. "I didn't think about it all race, and now suddenly I won the Tour."

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Dumoulin won the 20th stage by one second ahead of four-time champion Froome, who leapfrogged Primoz Roglic into third place overall.

Thomas finished third in the stage, 14 seconds behind. But that was more than enough with an advantage of more than two minutes at the start of the day.

"The strongest guy has won this Tour de France," Froome said. "Tomorrow, to stand up on the podium with G, it's going to be a really proud moment for me."

Thomas, known as "G," was a support rider during Froome's title rides but he became Sky's undisputed leader when Froome cracked in the grueling 17th stage through the Pyrenees.

Thomas and Froome have been together since their days on the small Barloworld team a decade ago.

"Because we've been teammates and friends for so long, it made it easier to communicate honestly," Froome said. "It was clear as soon as we hit the Alps that Geraint was in better physical condition than me. It was pretty simple, really."

Wearing an all-yellow skin suit on a bike in the red, white and blue colors of the British flag, Thomas was the last rider to start.

In a few drops of rain, Thomas was quick to regain control when his wheel appeared to lock up coming around a tricky, tight corner early on. Still, he was first at the two checkpoints before slowing in the final kilometers.

"I felt strong. I felt really good, actually. I heard I was up and maybe I was pushing it a bit hard on some of those corners," Thomas said. "Nico (Portal, Sky sports director) told me to relax, take it easy and just make sure I won the Tour. And that's what I did."

At the finish, Thomas let out a loud scream and held his arms out wide in celebration. He embraced his wife, Sara Elen, as soon as he got off his bike.

"The last time I cried was when I got married," Thomas said as he teared up.

Thomas is poised to become the third British rider -- and first Welshman -- to win the Tour after Bradley Wiggins and Froome. He will make it Sky's sixth victory in the last seven years.

"It's insane really -- just all the interest in Cardiff," Thomas said. "Great to put it on the map. We're a small nation and we really get behind anyone that's successful. By the sounds of it, it's gone pretty crazy back home, so looking forward to going back to celebrate."

An all-around rider who began his career on the track, Thomas helped Britain to gold medals in team pursuit at the 2008 and 2012 Olympics before turning his full attention to road racing.

Thomas claimed the yellow jersey by winning Stage 11 in the Alps, followed that up with another victory atop Alpe d'Huez a day later, and defended his advantage through the Pyrenees.

"He was in the shape of his life," Dumoulin said. "He didn't make any mistakes. He was never put into trouble by anyone, in the mountains or anywhere - including by myself."

The time trial world champion, Dumoulin clocked under 41 minutes over the hilly and technical 19-mile route.

It marked the first time in 12 years the Tour passed through the Basque Country, and fans waving the region's red, green and white flags lined the entire route in front of the area's traditional half-timbered houses.

It was Dumoulin's second career stage win in the Tour, having also won a time trial in 2016. The Dutchman has won six TTs overall at the three Grand Tours - the Tour, the Giro d'Italia and the Spanish Vuelta.