By the end of the day, with a little help from doctors and an Olympic gold medal in the men's normal hill, he was feeling just fine.
"When I woke up I felt a headache and I had a high temperature, but the doctors did everything they could do bring me to life and they did," Stoch said. "They did a good job, so thanks to them."
Jumping last in both rounds, the World Cup leader and winner of four World Cup events this season had marks of 105.5 meters and 103.5 meters, the best jumps in both rounds.
Peter Prevc of Slovenia took the silver and Anders Bardal of Norway the bronze.
The 26-year-old Stoch won by 12.7 points, the fourth- largest margin of victory in a men's normal hill at the Winter Games. It was Poland's first Olympic ski jumping gold medal since Wojciech Fortuna won the large hill at the 1972 Olympics.
"I feel like it's really not happened to me. Did this really happen?" Stoch said.
Stoch's coach Lukasz Kruczek said it nearly didn't.
"The whole day was crazy," Kruczek said. "The first information was that Kamil was ill. So we've been fighting every hour to make him better."
Prevc was pleased with second.
"I'm still collecting the best memories of my life," Prevc said. "My performance today was one of the best. I was struggling during training.
Thomas Morgenstern of Austria, returning from serious injuries from a fall during training a month ago, was 14th. Simon Amman of Switzerland, the defending champion from Vancouver in 2010 and who was seeking a record fifth Olympic gold medal, finished 17th.
It was another disappointing result by Austria's Gregor Schlierenzauer, the 2010 bronze medalist, who finished 11th Sunday. He has a record 52 World Cup victories, two Olympic bronzes but no gold.
"I'm really disappointed because the whole year I was talking about the Olympic Games and I couldn't get the best possible result," he said, crying. "The technique wasn't very good and my form was not stable for the whole season."
While the 7,500-seat stadium had only several hundred spectators for some of the training sessions, thousands crowded into the RusSki Gorki Jumping Center for the gold final.
Russian flags were most prominent, but there were also many fans from the jumping-mad countries of Poland, Austria and Slovenia. The locals cheered when word got around the venue that Russia had won its first gold of the games in team figure skating down on the coast.
Three Americans who qualified for the final didn't make it into the second round when the field was cut to 31. They were Nicholas Alexander of Brattleboro, Vermont (34th place), Peter Frenette of Saranac Lake, N.Y. (45th) and Anders Johnson of Park City, Utah (47th).
Earlier Sunday, Robert Kranjec of Slovenia withdrew from the final after suffering a knee injury in a landing fall during the qualification round on Saturday.
The men's next gold medal is in the large hill on Saturday, followed by the team large hill on Feb. 17.
Women jumpers, preparing for their first-ever gold medal event at the Olympics on Tuesday evening, hold their final training session Monday on the normal hill.