Chris Froome was overwhelmed after overcoming a turbulent Tour de France and Nairo Quintana's daring late attack up Alpe-d'Huez to effectively seal a second title.

The 2013 champion led nearest rival Quintana (Movistar) by two minutes 38 seconds entering the 110.5-kilometres 20th stage from Modane Valfrejus.

The 30-year-old Team Sky leader’s advantage was cut dramatically by the Colombian climber on the 13.8km finishing ascent and its 21 hairpin bends.

But Quintana ran out of road and trailed by 1min 12secs ahead of Sunday’s ceremonial finish in Paris, where Froome will stand atop the podium for a second time.

The imminent victory is all the more satisfying given the sustained innuendo and interrogations since Froome’s dominant win at La Pierre-Saint-Martin on stage 10.

“It’s overwhelming. We’ve been up against it all,” Froome said.

“There’s been so much going on in the background, away from the race, which could’ve taken a lot of focus away from what we needed to achieve.

“It feels as if we’ve been up against everything these last three weeks and to have still come out on top, it’s unreal.

“To have won the Tour once was a dream come true. To come back and do it a second time, that’s more than I could ever have imagined.”

Froome had endured similar scrutiny in winning the 100th Tour and first since Lance Armstrong was stripped of his record seven titles two years ago.

The performance-enhancing drug use of Armstrong and his contemporaries in the EPO era created a climate of suspicion around cycling, but Froome insists he races clean and there is no evidence to the contrary.

Froome was doused in urine, spat at and “attacked from every angle” on and off the bike.

“I was aware of a few people spitting again today, but 99 per cent of the crowds are absolutely fantastic,” Froome added.

“From a British point of view, the number of flags, Union Jacks... it’s heart-warming when you go past a group of guys and they go ‘come on, get stuck in lad’. It’s really special.”

Froome has been tight-chested and had a cough since Tuesday’s second rest day, but insisted he had made no application for special medication.

He was indebted to his team-mates for his victory, with Woet Poels and Richie Porte influential on the concluding climb of Alpe-d'Huez as he limited his losses to Quintana.

“Asking me here today, that probably was the hardest climb (of my career),” Froome added.

“I’ve done some pretty tough climbs in the last few years and this was definitely right up there.

“A lot of emotions going through my mind. There was a moment where I felt ‘this could go the other way, I’m in difficulty here’.

“I was on my absolute limits. I felt like I was dying a thousand deaths up Alpe-d’Huez today, but being with team-mates makes it a lot more manageable.

“I had a little bit left to do the last kilometre and try to limit those losses.”

Froome, who had targeted La Pierre-Saint-Martin as his moment to attack, was lauded by Team Sky principal Sir Dave Brailsford.

“Chris is the most unbelievable competitor and polite, nice guy off the bike but on the bike he’s the most resilient character,” Brailsford said on ITV4.

“The way he puts up with the abuse he gets, he’s so composed. A true champion. Britain doesn’t have many champions like this fella.”

Froome, who had squabbles with defending champion Vincenzo Nibali after stage six to Le Havre and Friday’s 19th stage to La Toussuire, added: “I try to be as polite as possible, but make no mistake about it: don’t take that for a weakness.

“Don’t take that as you can push me around. I’m going to stand up for what I believe in.”

Froome certainly stood his ground on Saturday.

Quintana’s first three attacks — on the Col de la Croix de Fer and twice on the lower slopes of Alpe-d’Huez — were snuffed out before a third surge saw him escape.

The Colombian finished 18 seconds behind stage winner Thibaut Pinot (FDJ) and Froome was 1:38 adrift in fifth place.

As well as overall victory, Froome emulated Robert Millar’s 1984 success by winning the polka dot jersey for King of the Mountains on the 40th anniversary of its introduction.

Quintana felt the Tour was lost on the second stage to Zeeland, where he was caught behind a crash and conceded 1:28 to Froome.

Quintana said: “I gave it everything. I lost the Tour in the first week when my team struggled with crashes, I lost a minute and a half, and that’s what cost me the Tour.”