With 60km left to ride, Primož Roglič (SLO) was brought down in a crash as pressure built on the breakaway, which was reduced to just four riders with a five minute lead.
Janse van Rensburg, Britton, Asgreen and Laengen were the riders left leading the race, as Britain’s Tao Geoghegan Hart and Spain’s Jonathan Castroviejo led the main bunch.
Around 25 riders made up the main group behind with 10km left to ride, including Adam Yates (GBr), Michael Woods (CAN), Gianni Moscon (ITA), Alejandro Valverde (ESP), Romain Bardet, Thibaut Pinot and Julian Alaphilippe (FRA).
Valgren was caught before the peak of the climb, and only Woods, Bardet and Valverde made it over the top together at the front of the race, with the rest of the favourites spread across road.
World Championship 2018 elite men’s road race, Kufstein to Innsbruck (259.4km)
This year’s World Championship road race was highly-anticipated due to the relentless climbing over the 259.4km route from Kufstein to Innsbruck.
With over 4,600 metres of vertical gain and some untested climbs with vicious gradients, it was hard to predict how racing would play out.
The peloton were happy to let the move escape, and the final breakaway was formed of Ryan Mullen and Conor Dunne from Ireland, Kasper Asgreen (DEN), Tobias Ludvigsson (SWE), Robert Britton (CAN), Daniil Fominykh (Kazakhstan), Karel Hnik (CZE), Vegard Stake Laengen (NOR), Jacques Janse van Rensburg (RSA) Laurent Dider (LUX) and Ilia Koshevoy (BLR).
Reigning world champion Peter Sagan (SVK) smiled and nodded to the camera as he fell away from the peloton on the same climb with 92km left on the clock.
1. Alejandro Valverde (ESP), in 6-46-41
2. Romain Bardet (FRA)
3. Michael Woods (CAN)
4. Tom Dumoulin (NED)
5. Gianni Moscon (ITAL), at 13 seconds .
6. Roman Kreuziger (CZE), at 43 seconds
7. Michael Valgren (DEN)
8. Julian Alaphilippe (FRA)
9. Thibaut Pinot (FRA)
10. Rui Costa (POR)
16. Peter Kennaugh (GBr), at 1-21
37. Adam Yates (GBr), at 4-00
Despite the calm in the peloton, a lot of riders felt the unrelenting nature of the course in their legs – both Irishmen in the breakaway Conor Dunne and Ryan Mullen were dropped from the front on the fourth ascent of Igls.
Olympic champion Greg Van Avermaet (BEL) kicked off a dangerous attack on a short, sharp climb near the finish with 54km remaining, followed by Damiano Caruso (ITA), and Omar Fraile from Spain.
Adam Yates had also held on until the final climb, but fell away on the savage slopes and finished 37th.
But the most daunting feature for those gunning for the rainbow jersey was the Höttinger Höll climb.
After completing the final lap of the finishing circuit, riders turned off to the savage final climb – 3.2km long, average gradient of 11.5%, but with a maximum of 28%.
Britain’s Ian Stannard took up workhorse duties at the front of the peloton and started to wind in the escapees, with Slovenia, Austria and France also contributing to the chase.
Racing was fairly sedate in the middle stages, the peloton leaving the breakaway with a 10-minute gap with 100km to ride.
Kennaugh faded quickly and linked up with a handful of chasers as Valgren pushed on at the front of the race over the crest of the climb.
But Alaphilippe was dropped early on the climb.
Alejandro Valverde has been crowned world champion after triumphing in a thrilling final to the elite men's road race in Innsbruck.
The 38-year-old Spaniard conquered the dreaded 28% gradients of Höttinger Höll and bested his strongest rivals in a four-up sprint at the line.
Valverde's win came after a brutal battle on the final climb, as Romain Bardet (FRA), Michael Woods (CAN) and Tom Dumoulin (NED) threatened to thwart his efforts.
The elite men’s course included the now familiar Gnadenwald climb after a week of racing in Innsbruck, which tested the legs 57km into the day at 2.6km in length with 10% average gradient.
Attacks came as soon as the flag dropped, but it took until around the 10km for anything with real conviction to stick.
The break pulled out a big advantage in a short time, hitting 20 minutes with around 200km left to rider.
But Valverde lead out the sprint in the final few hundred metres and took the win over Bardet and Woods who finished in second and third.
Roglič was able to rejoin the race on the penultimate lap.
Heading into the final lap, the breakaway's gap tumbled rapidly on the lower slops of Igls as Italy put up a unified front at the head of the peloton in anticipation of Höttinger Höll.
With just over 20km left to ride Asgreen and Laengen were caught, spelling the end for the day's early breakaway.
The small grouping of chasers were rejoined by the peloton on the descent as the Danish leader pulled out a 30 second gap heading into the foot of the dreaded Höll climb.
Höll immediately obliterated the bunch as the French team hit the front, with Valverde and Moscon holding on.
Racing then took the riders into a testing finishing circuit of 23.9km, and seven ascents of the 5.7% average, 7.9km long Igls climb.
From there, it was a fast and technical descent to the line in the centre of Innsbruck.
Britain's Simon Yates, Ireland's Dan Martin, Wout Poels (NED) and Michal Kwiatkowski (POL) were all dropped from the peloton.
At the front of the race, only Asgreen and Laengen remained from the breakaway with a 2-40 advantage at 35km left to ride, as a large peloton crested the climb.
Putting in a phenomenal ride, Dumoulin closed down the gap to the three out front on the flatter final 2km of the course, setting up the four-up sprint for the world title.
Dumoulin considered a surprise attack from the back of the group but was spotted by Valverde and bailed out of the move immediately.
Britain's best hope in the final was Peter Kennaugh, who attacked on the final climb and held a strong position to finish in 16th at 1-21 down on the winner.
That trio comfortably pulled out a 30 second advantage and prompted a slew of responses from the peloton, including by the German and Dutch teams.
Britain's Pete Kennaugh put in the first big attack of the final, opening a gap near the top of Igls and joined by Michael Valgren (DEN).
Valverde then lead out the sprint in the final few hundred metres, holding off second place Romain Bardet to win his first World Championship road race at 38 years old.
How it happened
Canada, Sweden and Denmark sent riders off the front, with Ireland sending men out to join the move, eventually forming an 11-man breakaway.
Van Avermaet's group were caught on the penultimate run up Igls, but the injection of pace put big names under strain.
The Valverde trio began the run in to the line, with Dumoulin the next rider behind trying to chase down the leaders.
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