Italian wins in front of home fans as he beats two-time reigning champion Rohan Dennis, who finished fifth.
Italy's Filippo Ganna blitzed through the course on home roads to win the men's time trial world title in Imola.
The four-time track world champion completed the 31.0 km lap around the Emilia-Romagna region, which ended at the Autodromo Internazionale Enzo e Dino Ferrari race track, in 35 minutes 54.10 seconds.
In doing so, he became the first Italian to become the elite men's time trial world champion.
"It's a dream for me and I'm really happy," he said after the race. "I don't have the words. I won four rainbow jerseys on the track. This is my first in the time trial. I will celebrate with my family."
Belgium's Wout van Aert, fresh off the back of a long Tour de France with Jumbo-Visma, won the silver, while European champion Stefan Küng of Switzerland won bronze.
The two-time defending champion, Rohan Dennis of Australia, struggled home in fifth, behind Great Britain's Geraint Thomas who was competing in his first world championship time trial.
Britain's Thomas set the mark to beat for the favourites, coming across the line in 36 minutes 31 seconds.
Not bad, considering the Welshman rarely rides individual time trials outside of stage races - this was his World Championships debut in the event.
Before Friday's race, Thomas had told the Olympic Channel: "It's the first time I've actually come to the road Worlds feeling in shape, in my best shape.
"This is the first time I've done a TT (time trial) that's not in a stage race for a while, so it's different to what I'm used to, really. It'll be a good hit out."
It seemed for a while like he might make it onto the podium as rider after rider crossed the finish line at the Autodrome behind him, including two-time European time trial champion Victor Campenaerts of Belgium.
Ganna, Campenaerts, Dennis, and Thomas finished in that order on a shorter time trial on the last stage of the Tirreno-Adriatico last week, and all four were heavily favoured to do well here.
But the Belgian could never match Thomas' pace and was out of the picture early.
Two men who raced at the Tour de France - van Aert and Küng (although the latter withdrew before the final week to focus on this time trial) - managed to upstage the lot.
Van Aert, an impressive all-around rider who is also one of the favourites to win the road race on Sunday, finished fourth in the Tour's uphill time trial, and showed once again why he is a rider to watch in all sorts of parcours.
He took 10 seconds off Thomas' time at the line, only to have a nervous wait as Küng came in just three seconds behind.
After Ganna smashed van Aert's time by 27 seconds at the line, all eyes were on Dennis.
However, the Australian seemed out of form even with a tailwind helping him in the second half of the race, finishing 40 seconds down.
While it was a disappointment for him, his trade team Ineos Grenadiers may well consider the race a success, with three of their riders - Ganna, Thomas, and Dennis - placing in the top five.