Michał Kwiatkowski triumphed at Milan-Sanremo in a staggering sprint victory against world champion Peter Sagan.
Sagan had produced an astonishing acceleration on the final climb, the Poggio, which only Kwiatkowski (Team Sky) and Julien Alaphillipe (Quick-Step Floors Pro Cycling Team) could match.
Before that it had looked to be a day when a large group of favourites would have a chance to contest the win - a select group of around 70 riders had gone clear as the finish line beckoned.
But Sagan had other ideas and the pre-race favourite's brutal attack after 285km of racing blew away almost all of his rivals.
The chasing teams were desperate to make the catch after so much hard work but Sagan's power was too much them. However, Kwiatkowski had the final word, emerging from behind the Slovakian's wheel in the final metres and snatch victory from his long-time rival.
Alaphillipe took third while Alexander Kristoff (Team Katusha Alpecin) won the bunch sprint for fourth place. Fernando Gaviria (Quick-Step Floors Pro Cycling Team) was fifth and last year's winner Arnaud Démare of FDJ was sixth.
Read Velon's Milan-Sanremo data summary
Much earlier in the day a 10-man breakaway formed, going clear after just 5km. They stayed away until the penultimate climb of a typically punishing 291km day in the saddle - the longest one-day race in professional cycling.
Nico Denz (Ag2r La Mondiale), Mattia Frapporti (Androni-Sidermec), Mirco Maestri (Bardiani-CSF), William Clarke and Tom Skujins (both Cannondale-Drapac Pro Cycling), Ivan Rovny (Gazprom-Rusvelo), Alan Marangoni (Nippo-Vini Fantini), Umberto Poli (Team Novo Nordisk), Federico Zurlo (UAE Team Emirates) and Julen Amezqueta (Wilier-Selle Italia) were the riders in the break.
With 100km to go – and 191km already on the clock – the gap stood at a very manageable 2’16”, but the sprinters’ teams were mindful of the strong coastal winds en route that would potentially make the chase more challenging.
With 80km remaining the gap had stretched to 2’44” but came back to 1’22” with 50km left.
Alexis Gougeard (Ag2R-La Mondiale) jumped out of the bunch a few kilometres later, on the Capo Cervo, and tried to bridge across to the leaders but failed to make the effort stick.
With 35km left and the Cipressa beckoning, the advantage of the breakaway had diminished to 50” and the front group was down to seven.
There was a seemingly endless long-list of potential winners and the big hitters were still in the mix – from Sagan to Gaviria, Démare, Michael Matthews and Greg van Avermaet.
Bahrain-Merida, Cofidis and Team Katusha-Alpecin were among the teams working at the front of the peloton as Rovny of Gazprom-Rusvelo cranked up the pace at the front.
Tim Wellens (Lotto Soudal) struck out on his own with 35km to race as the peloton made its way up the Cipressa – the penultimate climb. Team Sunweb and Simon Geschke soon raised the tempo at the front again, putting plenty of riders under pressure with 260km already raced.
On the fast descent off the Cipressa and inside the 20km mark, it was Bahrain-Merida at the front of an increasingly strung-out peloton.
It was Gallopin’s turn to try an attack which was covered by Phillipe Gilbert of Quick-Step Floors Pro Cycling Team. A front group of around 70 riders formed and it looked for all the world like a bunch sprint would result.
With 10km to race the situation was predictably hectic as the favourites’ teams fought for position. Trek-Segafredo were working for John Degenkolb as Koen de Kort put in a huge turn at the front.
Meanwhile Team Sky were massed at the front of the peloton as they sought to set up Elia Viviani or even the in-form Kwiatkowski who won Strade Bianche two weeks ago.
Quick-Step Floors Pro Cycling Team were working for Gaviria while Team Sunweb had high hopes for Matthews, as his Dutch team-mate Tom Dumoulin turned up the heat at the front and looked over his shoulder to see who would respond.
With 7km to go the riders also hit seven hours in the saddle and were anticipating a bunch sprint finish on Via Roma. But there was a twist to come - albeit a seemingly inevitable one as Slovakian Sagan burst clear.
Alaphillipe and Kwiatkowski were the only two riders who had the legs to respond and they had to give everything they had to stay on Sagan's wheel and form a late three-man breakaway. They had forged what looked like a decisive advantage with 4km to race heading down the final descent.
The riders calculated they had time to sit up for a short game of cat-and-mouse in the final kilometre, with no-one wanting to show their hand too early.
The front group was rumbling ever closer and was within sight of the three at head of the race, and as Kwiatkowski bided his time on Sagan's wheel, the Slovakian opened up his sprint.
Kwiatkowski's waiting game paid off as he allowed the world champion to lead him out, and emerged to his left to produce one final, enormous effort to get past.
As both riders flung their front wheels for the finish line, it was Kwiatkowski, the world champion in 2014, who had edged just in front. A scintillating end to a true classic.