BEIJING — The tears started flowing from Jen Lee’s eyes the moment the horn sounded to signal that the United States had beaten Canada, 5-0, to win its fourth consecutive gold medal in Paralympic sled hockey.Lee cried in front of the goal as he celebrated with teammates. He cried as the players gathered to shake hands with the vanquished Canadians, and he cried again as he waited to accept his medal at China’s National Indoor Stadium on Sunday.Lee had won two gold medals previously, at the 2014 Sochi Games and the 2018 Pyeongchang Games. But not like this.During the previous 12 years he was the backup to Steve Cash, the longtime U.S. goalkeeper who is considered by most experts to be the best sled hockey goalie ever. Lee finally got his chance to start when Cash retired last October, and there was some question about how the United States would fare without him.Lee did just fine. He did not allow a goal in four games here. But shaking off the pressure of replacing Cash and producing an equally impressive performance to win gold were not what made him so emotional, he said.Instead, he described his move to the United States from Taipei, Taiwan, with his family when he was 8 and how he had dreamed of being an athlete and a “G.I. Joe.” He detailed how he joined the U.S. Army, how he lost his right leg in a motorcycle accident and how he then learned to play sled hockey. He explained the significance to him of the immigrant experience and of serving his country, first as a soldier, and now, as an athlete.“All of those things came to me,” he said, “because, you know, I am 35 years old.”Hence the emotion and the tears, and for most of the other 16 U.S. players and the head coach, David Hoff, it all made sense. Lee’s performance was the key to another U.S. gold, and this time he was not a bench player.“He’s been the backup goalie for as long as I’ve been in the program,” said Jack Wallace, a U.S. defenseman. “He put in the time, the hours and the work.” Referring to the team’s opponent on Sunday, he added: “They had a bunch of A-1 chances today, and to have a rock wall behind us was everything.”Lee made several good saves, including one on a breakaway in the first period when the score was still close. Canada’s goalie, Dominic Larocque, said the game might have been decided then.“If we score a goal there, maybe it changes the whole game,” he said.But only the United States managed goals. Declan Farmer and Brody Roybal scored two apiece, and Josh Pauls, the captain, potted one, too. Overall, the United States outscored its opponents in this Paralympics, 30-1.It was certainly not that easy four years ago in Pyeongchang, when the United States faced doom in the gold medal game with under a minute to play in one of the most dramatic hockey games in recent memory. Canada led, 1-0, and when the Americans pulled Cash to get an extra skater on the ice, Canada hit the post with what could have been a game-icing goal.With new life, Farmer scored with 38 seconds to play and then added the overtime winner. That memory was seared in the minds of the Canadians over the last four years, and they came to Beijing seeking revenge and their first sled hockey gold medal since 2006.After Canada thrashed South Korea, 11-0, in the semifinal round, Tyler McGregor, Canada’s captain, said anything short of the gold was not good enough. Indeed, after Sunday’s loss, the Canadians could not conceal their disappointment at the ceremony, accepting their silver medals the way a child might take a serving of steamed kale.Through his own tears, McGregor said it was an awful feeling to lose again, but he described an overwhelming sense of pride for the work his teammates and staff put into the last four years.But Canada, so close to winning the gold in Pyeongchang four years ago, lost to the United States twice at these games by 5-0 scores, suggesting the Americans may actually have widened the gap.“We refuse to believe that,” McGregor said as he choked back the tears. “You have to maintain that belief.”Pauls, who became the first sled hockey player to win four gold medals, indicated the United States probably has increased its lead over the rest of the world, although he and other U.S. players acknowledged the role the pandemic played in this Olympic cycle. The United States might have had an advantage in preparation over countries, like Canada, that had stricter anti-infection rules.But Pauls also noted that this U.S. team was a more tight-knit group than any of the others he played on, and it led to remarkable dedication and hard work, he said, especially from Lee.And if four lopsided scores were not enough of a warning that the United States did not plan to ease its grip on world sled hockey dominance, Pauls used words, too.“We have the blueprint and we set the tone,” he said. “It’s going to be up to the other countries to match it.”Amy Chang Chien contributed reporting.