Sir Bradley Wiggins had to settle for silver as Tony Martin won his third consecutive world time trial title with a dominant performance in Tuscany.
The 28-year-old German produced a magnificent display on a largely flat 57.9km course, comfortably beating Wiggins by 46 seconds and third-placed Fabian Cancellara, of Switzerland, by 48 seconds.
While Wiggins made a slow start, both Martin and Cancellara tore through the opening sector and were neck and neck at the first intermediate split point, after 7.3km.
But then Martin stepped up a gear and proceeded to establish a substantial lead on his two main rivals that was never in danger of being closed.
Wiggins appeared set for bronze when he trailed Cancellara by 24 seconds at the second split, after 24.3km, but he then produced a strong final two sectors to gradually reel the Swiss back in and snatch silver at the death by just two seconds.
Britain's other representative in the race, Alex Dowsett, had a difficult day and could only finish 5min 46sec behind Martin in 41st.
The race had been one of the most hotly anticipated time trials in years, with Martin, Wiggins and Cancellara all travelling to Italy in prime form having all won WorldTour time trials in the build-up.
The trio were the last three men on the course and while they waited, Kanstantsin Siutsou (Belarus) went about posting an early fastest time of 1hr 8min 36sec.
His split times were soon swept aside by the top seeds, though, as Martin and Cancellara both made ferocious starts.
Wiggins fights back
The pair were separated by just 0.36 seconds at the first split and with Wiggins only fourth fastest, 15 seconds back, it appeared a much-vaunted three-way battle for the rainbow jersey was already down to two.
By the second split, Martin had distanced Cancellara by 13 seconds and when that became 28 seconds by the final split, at 42.3km, the title was effectively his and attention turned to the fight for silver.
Cancellara had looked comfortable at the second split, but he saw his advantage over Wiggins halved to 12 seconds by the final split, 15.6km from home.
Now holding the momentum, the Briton proceeded to erode the rest of a tiring Cancellara's lead as the pair entered Florence, and they were inseparable with just 2km remaining. Wiggins still had reserves of energy, though, and stole ahead to claim his second world time trial silver medal.
1 Tony Martin (Ger), 1:05:36
2 Bradley Wiggins (GB), +46secs
3 Fabian Cancellara (Swi), +48
4 Vasil Kiryienka (Blr), +1:26
5 Taylor Phinney (USA), +2:08
6 Rasmus Quaade (Den), +2:36
7 Marco Pinotti (Ita), +2:41
8 Adriano Malori (Ita), +2:51
9 Gustav Larsson (Swe), +2:58
10 Kanstantsin Siutsou (Blr), +2:59
41 Alex Dowsett (GB), +5:46