Britain's Jamie Nicholls produced a stunning second run to qualify automatically for the slopestyle final.
It was the first event of the Winter Olympics in Sochi - ahead of Friday's official opening ceremony.
"I can't believe what I've done," said Nicholls, who was seventh after the first run but scored 86.75 in the next round to move up to fourth.
Team-mate Billy Morgan was sixth but has another shot at qualification via Saturday's semi-finals.
In each heat, the top four competitors after their two runs were given an automatic passage into the final with the remaining snowboarders left to fight for four remaining places.
In the women's competition, triple X Games gold medallist Jenny Jones and Aimee Fuller will also need to go through the semi-finals after they finished fifth and 10th respectively.
Slopestyle is making its Olympic debut in Sochi, but much of the pre-event talk was focused on the controversial course.
Norwegian medal prospect Torstein Horgmo was ruled out of the Games after breaking his collarbone in training on Monday.
Two-time US Olympic champion Shaun White claimed the course was "a little intimidating" and subsequently withdrew from the slopestyle event to focus on claiming a third halfpipe gold medal.
Although happy with his overall performance at the Sochi 'Extreme Park', Morgan felt being the first athlete to compete at the 2014 Winter Olympics may have hampered his prospects in the opening round.
"It is a bit of a disadvantage as I don't get to see what everyone has done," said the 24-year-old snowboarder. "It was a good clean run today and I'm pleased to show what I can do."
There was confusion after the end of qualification.
Olympic officials had informed the media that only two athletes from each heat would progress automatically to the finals.
But Nicholls, 20, secured his place despite finishing fourth.
"My dream was to get to the final, I'm so happy to make it in my first Olympics," he said.
Canadian Max Parrot achieved the highest score across the two qualification heats with 97.50 just .50 down in the highest ever slopestyle score which was achieved by Canadian Mark McMorris at the 2013 X Games.
Jones was first down the course in the women's event and missed out on an automatic place in the final by 4.75 points.
"I was happy with my first run," she told BBC Sport. "It's just a shame that I messed the second one up.
"The course demands a lot of respect, it has big features and big rails and you certainly need to have your wits about you."