Italian Ganna went into the race as the favourite after his dominant performance in the final stage time trial at Tirreno-Adriatico, but he faced stiff competition from his Ineos Grenadiers team-mates.
Reigning champion Dennis (Australia) was an unknown quantity heading into the race, with the course tipping the balance in his favour slightly, while Geraint Thomas has been in outstanding form as he prepares for the Giro d’Italia.
But it was 24-year-old Ganna who ripped around the course fastest, ahead of Wout van Aert (Belgium) in second and Stefan Küng (Switzerland) third.
The British riders put in a strong showing but couldn’t quite make the medal places, as Geraint Thomas finished fourth and Alex Dowsett ninth.
How it happened
It was the turn of the elite men to hit the 31.7km-long TT course in Imola on Friday (Saturday, 25), with some unpredictable conditions to deal with.
The mostly flat out and back circuit was a rapid course, with just a single 400m, six per cent climb for the riders to tackle 26km into the ride.
With high-speed and straightforward opening half followed a slightly technical final 8km, this course would suit those riders specialising in the discipline and who spend a lot of time on their TT bike.
Rain started to fall on the first riders out, but had cleared up by the time the favourites hit the course, however the wind was up with riders forced to battle through headwind gusts on the way out, and then being bolstered by strong tailwinds on the way home.
Early in the day we saw some strong benchmark times, most notably from Italy’s Eduardo Affiini who set the provisional fastest time of 37-25- to hold the hot-seat as the favourites set out onto the course.
But it was Geraint Thomas, who set off midway through the field, who absolutely blasted the first half of the course and was 25 seconds faster than Affiini at the 14.9km timing check.
Thomas continued to press hard in the tricky final section of the course and hit the famous Imola racing circuit well ahead of Affini’s time, with the Welshman setting the new fastest time of 36-31 at the line, more than a minute ahead of Affiini.
Eyes then turned to the rest of the favourites, with Wout van Aert, Stefan Küng and Victor Campenaerts all riding strong after 15km but failing to beat Thomas’s time at the intermediate check.
Then it was the turn of pre-race favourite Filippo Ganna to hit the roads, the Italian crushing the first half of the course and smashing Thomas’s intermediate time by almost 40 seconds, setting a time of 18-05 after 15km.
Not far behind reigning world champion Rohan Dennis was trying to chase down the time set by his Ineos team-mate, and while the Australian was faster than Thomas at the mid-way point, he was still 20 seconds behind Ganna.
Wout van Aert pulled out a phenomenal return leg of the course however and finished 11 seconds faster than Thomas to set the new fastest time, as Thomas’s chances of a podium slimmed.
Küng then crossed with the second fastest time on the day behind Van Aert , pushing Thomas into third place with Dennis and Ganna still out on the road.
But attention then fell on Filippo Ganna who entered the Imola circuit with a huge buffer on the rest of his rivals, finishing with a time of 35-54 and an average speed of 52.9km/h, 26 seconds ahead of Van Aert.
Dennis was the only man who could trump Ganna, but it would take a special performance to overcome the deficit.
Despite looking strong out on the course, Dennis didn’t have the power to close the gap to Ganna and instead slipped back in the closing kilometres, by the finish he had slipped to fifth place, 39 seconds off the race win.
After an outstanding performance Thomas finished fourth, up there with some of the best TTers in the world and a great sign ahead of his Giro d’Italia ambitions.
Britain’s other hopeful Alex Dowsett put in a great ride but was unable to match the pace of the favourites, finishing ninth, 1-06 off Ganna’s time.
Imola 2020 World Championships, elite men’s time trial: Imola to Imola (31.7km)
1. Filippo Ganna (Ita), in 35-54
2. Wout van Aert (Bel), at 26s
3. Stefan Küng (Sui), at 29s
4. Geraint Thomas (GBr), at 37s
5. Rohan Dennis (Aus), at 39s
6. Kasper Asgreen (Den), at 47s
7. Rémi Cavagna (Fra), at 48s
8. Victor Campenaerts (Bel), at 52s
9. Alex Dowsett (GBr), at 1-06
10. Tom Dumoulin (Ned), at 1-14