Pre-race favourite Filippo Ganna won his maiden individual time trial world title on home soil as the Italian crushed his rivals over 32 kilometres on Friday.
The 24-year-old, a four-times individual pursuit world champion on the track, clocked 35 minutes 54.10 seconds to beat Belgian Wout van Aert by 26.72 seconds.
Swiss Stefan Kung took third place, 29.80 seconds off the pace, as Australian Rohan Dennis, who had won the two previous titles, ended up a disappointing fifth.
"It's a dream for me, I had great support from the team car, I want to thank the whole Italian team," said Ganna, who had geared up for the event by winning the individual time trial on the Tirreno-Adriatico stage race earlier this month.
"I had no pressure. I was coming for a podium finish having won four rainbow jerseys on the track already."
Ganna is the first Italian to win the individual time trial at the road world championships.
Briton Geraint Thomas, who is gearing up for next month's Giro d'Italia, finished an encouraging fourth after making a fast start despite racing without his GPS unit.
"I warmed up on a different bike and then I got to my race bike and it wasn't there. People were running around looking for it... No idea. Someone (messed) up, but that's the way it goes," Thomas was quoted as saying by Cycling News.
"I only got my race bike three minutes before the start and I was like, 'Where's my Garmin?' They gave me a spare one and I was frantically pairing that. Then I went to put it on and it was too big to fit on, so I was like, jeepers, but that's just the way it goes."
Dutchman Tom Dumoulin, the 2017 champion, endured a bad day at the office, narrowly avoiding a crash in the finale and finishing 10th, more than one minute off the pace.
Chaos was narrowly avoided as the finish line arch collapsed about half an hour after the last rider, Dennis, completed his ride.
"Due to the very strong wind today, the finish arch fell down in the late afternoon, after the end of the race," the UCI said in a statement.
"The staff of the organising committee and the UCI are working to ensure the equipment is in perfect working order for tomorrow’s race."
The road world championships continue on Saturday with the women's race.
(Writing by Julien Pretot; Editing by Toby Davis and Ken Ferris)
