Chris Froome extended his dominance of this year's Tour de France with a second stage win, this time on the 17km uphill time trial to Megeve.
The Team Sky rider entered the day with almost two and a half minutes' advantage over his rivals and showed his determination to add to that with a convincing Stage 18 display that will also make him one of the favourites for gold when the riders go against the clock in Rio next month.
With just two more mountain stages and the ceremonial ride into Paris to come, Froome now leads second-placed Bauke Mollema by three minutes and 52 seconds.
Ireland's Dan Martin finished a respectable 18th on the day in a time of 32:11, but nonetheless dropped one place in the general classification, to 10th overall, as South African Louis Meintjes leapfrogged the Etixx QuickStep rider by just three seconds.
Martin's time was 1:28 slower than Froome, who completed the testing climb in the shadow of Mont Blanc in a time of 30:43, snatching the stage from long time leader, Dutch time-trial specialist Tom Dumoulin, by 21 seconds.
Dumoulin won the other time trial of this Tour, stage 13 to La Caverne du Pont d'Arc, and had been seen as the favourite again here but could not match Froome in the latter part of this course.
The steepest climbs came in the first half of the stage on the Cote de Domancy, but it was after that point that Froome picked up 44 seconds on the Dutchman.
"I really didn't expect to beat Tom today," Froome said. "I think pacing was key today. I really started off quite steady and really controlled that first part and then just gave it everything I had over the last part.
"Really, really happy with that."
With Froome almost out of sight the coming days in the Alps could instead see a real battle fought out for the remaining steps on the podium.
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 him 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.
Romain Bardet and Richie Porte also made up time on Mollema and Yates and are both now within 45 seconds of the podium.
