Chris Froome won the stage 18 time trial from Sallanches to Megeve to strengthen his overall lead in the Tour de France.
The Team Sky rider completed the testing 17km stage in the shadow of Mont Blanc in a time of 30 minutes 43 seconds.
His second stage win of this Tour came by 21 seconds from Dutch time-trial specialist Tom Dumoulin, but Froome’s first priority was to pick up time in the general classification.
He did that by some margin, and now leads second-placed Bauke Mollema by three minutes and 52 seconds with two mountain stages left before the traditional parade into Paris.
Adam Yates put in a fine ride and the 23-year-old Briton picked up a couple of seconds on Mollema, leaving him 24 seconds further back in third place.
However, Yates saw his advantage over fourth-placed Nairo Quintana cut to 21 seconds as the Colombian put his podium place under pressure.
Quintana had been expected to be Froome’s biggest rival in this Tour but he now sits four minutes and 37 seconds off yellow.
Froome took the yellow jersey with a surprise downhill attack to win stage eight to Bagneres-de-Luchon. His second stage win of this Tour takes him to seven in his career.
The 31-year-old continues to close in on what would be a third Tour title following his successes in 2013 and 2015.
Chris Froome extended his advantage in the yellow jersey as Ilnur Zakarin won stage 17 of the Tour de France to Finhaut-Emosson.
After Katusha’s Zakarin took stage honours up the road, Froome raced clear of Adam Yates and Nairo Quintana late on the final climb while Bauke Mollema, who started the day second overall, was dropped by the group of contenders.
As Froome crossed the line alongside former team-mate Richie Porte, Quintana was dropped by Yates as his hopes of challenging Froome for yellow were dealt a severe blow.
The provisional general classification showed Team Sky’s Froome two minutes and 27 seconds clear of Trek-Segafredo’s Mollema, while 23-year-old Briton Yates of Orica-BikeExchange was third, two minutes and 53 seconds back.
But most encouraging of all for Team Sky will have been the sight of Quintana completely unable to respond as the attacks began as the Movistar man finished 20 seconds behind Yates.
The Colombian has usually come on strong in the third week of Grand Tours and threatened Froome’s position in yellow late in last year’s Tour, but does not appear to have the legs to rival him again.
Race leader Chris Froome came home in a much-reduced peloton at the end of the 209km stage from Moirans-en-Montagne to Bern in Switzerland to maintain his advantage in the yellow jersey competition.
Slovak Sagan claimed his third victory at the Tour this year and seventh in total in the third photo finish of the 2016 race.
This victory ensured this will go down as Sagan’s best Tour yet, having also held the yellow jersey for three days during the first week.
He won the second and 11th stages before this, but his third stage victory outstrips the two gained in each of 2012 and 2013.
And as he’s well on his way to winning a fifth straight green jersey, the 26-year-old is enjoying his best Tour yet — and the best season of his career.
He was world champion back in September and then won his first prestigious “Monument” one-day classic at April’s Tour of Flanders.