Remco Evenepoel cut Tadej Pogacar’s lead at the top of the general classification by 28 seconds with a dominant victory in the time-trial on stage 16 of the Tour de France.
Olympic champion Evenepoel completed the 26.1km course along the shores of Lake Geneva in 32 minutes and 19 seconds.
It was the 26-year-old Belgian’s second successive stage victory after he triumphed on Sunday’s mountainous 15th stage.
Slovenia’s Pogacar crossed the line in 32min and 47secs as his overall lead was trimmed to 4min 32secs.
The rest of the field finished more than a minute back, with Denmark’s Mattias Skjelmose taking third.
Evenepoel acknowledged it was “pretty special” to secure his fourth Tour stage victory overall on Belgium’s national day.
“It’s amazing, it was a very nice time-trial with a lot of people on the side of the road,” Evenepoel said.
“I read this morning it’s been a while since Belgium won on national day, so I’m proud to be the one.
“My whole family from both sides being here, my parents came just today. My wife is here with her parents and the siblings as well.”
Evenepoel’s team-mate Florian Lipowitz suffered a setback, though, after he was forced out of the stage through injury.
Two days after two-time former winner Jonas Vingegaard crashed out of the Tour while sitting second overall, Lipowitz went down hard on a bend.
The German had been fifth in the standings until that point and had set the fourth fastest time in the three intermediate time-checks.
But several minutes after he crashed, Lipowitz was escorted to a medical vehicle holding his left arm.
“That’s very unfortunate, it’s like a bitter-sweet pill to swallow with this victory, so I wish him all the best and I hope it’s not too bad,” Evenepoel added.