Wout van Aert's sensational escape in the final 10km of stage four gave him his first win at this year's Tour de France and extended his overall lead.
The Belgian had finished second in each of the first three stages of this year's race but this time his plan worked to perfection.
A breathtaking attack up the final climb sent him clear and he held on in the closing kilometres into Calais.
Van Aert moves 25 seconds clear in the General Classification.
Behind him, Jasper Philipsen won a bunch sprint to the line and raised his arms thinking he had won the stage, illustrating the chaotic nature of the finish.
That was all down to Van Aert's attack, with a cross tailwind helping to split the pack as they tried to stay with him.
Van Aert had been denied a stage win by a photo finish in a bunch sprint as the Tour left Denmark on Sunday, but marked the first day of racing in France with a memorable triumph.
"I didn't want to take the risk anymore," he said afterwards about the move by his Jumbo-Visma team on the way up up Cote du Cap Blanc Nez.
"It was quite obvious that we were trying something with the team," he explained.
"We were in a perfect position thanks to Nathan (van Hooydonck) and Stevie (Kruijswijk), then Nathan opened up on the climb, Tiesj (Benoot) took over and we heard on the radio there was some damage.
"The goal was to go full to the top and see what happened, but then I came over the top alone.
"I was a bit in doubt whether I should wait for Jonas Vingegaard and Adam Yates behind me, but by going full, I also put Jonas and the others in a good position because they didn't have to ride.
"So I decided to go on alone, and then it was 10km of all-out suffering."
Last year's winner, Tadej Pogacar, and the other leading contenders for the General Classification recovered to finish together in the group immediately behind Van Aert but, along with the pure sprinters in the race, they were unable to organise themselves in time to catch him.
The 27-year-old flapped his arms before punching the air in triumph as he crossed the line in yellow, and later explained his celebration by saying "this jersey gives you wings".
Stage four results
1. Wout van Aert (Bel/Jumbo-Visma) 4hrs 01min 6secs
2. Jasper Philipsen (Bel/Alpecin-Deceuninck) + 8secs
3. Christophe Laporte (Fra/Jumbo-Visma) Same time
4. Alexander Kristoff (Nor/Intermarche) Same time
5. Peter Sagan (Svk/TotalEnergies) Same time
6. Luca Mozzato (Ita/B&B Hotels) Same time
7. Danny van Poppel (Ned/Bora-Hansgrohe) Same time
8. Hugo Hofstetter (Fra/Arkea-Samsic) Same time
9. Michael Matthews (Aus/BikeExchange-Jayco) Same time
10. Benjamin Thomas (Fra/Cofidis) Same time
General classification after stage four
1. Wout van Aert (Bel/Jumbo-Visma) 13hrs 02mins 43secs
2. Yves Lampaert (Bel/Quick-Step Alpha Vinyl) +25secs
3. Tadej Pogacar (Slo/UAE Team Emirates) +32secs
4. Mads Pedersen (Den/Trek-Segafredo) +36secs
5. Mathieu van der Poel (Ned/Alpecin-Deceuninck) +38secs
6. Jonas Vingegaard (Den/Jumbo-Visma) +40secs
7. Primoz Roglic (Slo/Jumbo-Visma) +41secs
8. Adam Yates (GB/Ineos Grenadiers) +48secs
9. Stefan Kung (Swi/Groupama - FDJ Same time
10. Tom Pidcock (GB/Ineos Grenadiers) +49secs
12. Geraint Thomas (GB/Ineos Grenadiers) +50secs
80. Chris Froome (GB/Israel-Premier Tech) +2mins 20secs