Two-time Tour de France winner Jonas Vingegaard seized control of Paris-Nice with victory on Wednesday's rain-soaked fourth stage.
The Danish rider launched a decisive attack one kilometer from the finish of the 195km stage from Bourges to Uchon, distancing Red Bull-BORA-hansgrohe teammates Daniel Martinez and Tim Van Dijke on the steep final climb.
Martinez finished second at the summit, 41 seconds behind, and now trails Vingegaard by 52 seconds in the overall standings of the eight-day race.
German rider Georg Steinhauser sits third overall at 3 minutes 20 seconds after finishing fifth on the stage, nearly three minutes behind the winner.
Vingegaard said he expected a difficult day in the saddle and joked that the frantic start meant he never had time to remove some of the heavy clothing he wore in the bad weather.
"Maybe you can call me a trendsetter with the long pants," Vingegaard said. "I just didn't have time to take clothes off."
"The start was so hectic, I'm just so happy I'm here and I've won the stage," he added, thanking teammate Edoardo Affini for helping pace him into the decisive group.
Juan Ayuso Crashes Out As Paris-Nice Conditions Worsen
Early crosswinds caused chaos and split the peloton into multiple groups before heavy rain made conditions increasingly dangerous.
The slick roads led to several crashes, including one involving overnight race leader Juan Ayuso.
Ayuso was taken away by ambulance and another overall contender, UAE Team Emirates rider Brandon McNulty, also abandoned after a heavy fall.
Lidl-Trek later confirmed that Ayuso had avoided any serious injuries after scans revealed no fractures.
Eleven riders failed to finish the stage.
Red Bull-BORA-hansgrohe teammates set the pace late in the race for Martinez until he and Vingegaard were the only general classification contenders left battling for the stage victory.
INEOS Grenadiers rider Kevin Vauquelin fought back to sixth place despite being dropped earlier in the crosswinds, leaving him fourth overall at 3 minutes 39 seconds.
Three hilly stages and a major mountain stage on Saturday remain, with Thursday's fifth stage featuring an uphill finish after three climbs in the final 40km.