GANGNEUNG - The Olympic Athletes from Russia and United States were shock losers Wednesday as the first Winter Olympic men's hockey tournament in 24 years without NHL players produced plenty of drama and thrills.

Slovakia's Peter Ceresnak scored the game-winning goal with 11:30 remaining in a 3-2 victory over the favoured Russians by a team assembled days ago by a Canadian coach who can't even talk to all his players. Slovenia's Jan Mursak, a forward for Swedish side Frolunda, scored the equaliser with 97 seconds remaining in regulation time and netted the winner 38 seconds into over-time for a 3-2 comeback shocker over the Americans in group-stage play at Pyeongchang.

Jordan Greenway, a Boston University star who became the first African-American player on a US Olympic hockey team, scored in a losing cause. The upsets ended any notion the Olympic Athletes from Russia would have an edge based on familiarity with a roster taken from the two top teams in the Russia-based Kontinental Hockey League.

National Hockey League owners had sent players to the Olympics since 1998 but money and injury issues pushed them not to shut down this season for players to compete, so most rosters are stocked from the KHL and other European circuits.

Russia's talent pool hasn't taken Olympic gold since 1992 but it sizzled early. Vladislav Gavrikov scored on a slapshot 2:54 into the contest and just 74 seconds later Kirill Kaprizov bounced in a deflection. But Peter Olvecky answered for Slovakia with 3:55 remaining in the first period and Martin Backos equalised 1:50 later, setting the stage for Ceresnak's decider from the top of the slot.

Canadian coach Craig Ramsay, charged by Slovakian general manager Miroslav Satan with producing more goals, assembled the squad in a week, fighting a language barrier with many of his players.

"Most of them have an idea and some can really speak (English) but a few not. I always have to make sure I grab a player," Ramsay said. "The problem is if I get excited and speak faster, even the guys who know it don't get it."

Russia's flag and team name were banned by the International Olympic Committee over the Sochi doping scandal but dozens of fans cheered "Russ-i-a" and waved Russian flags. The Americans, who play the Russians on Saturday, took a 1-0 lead 17:44 into the game on a goal by KHL Helsinki Jokerit forward Brian O'Neill, who assisted on Greenway's goal 12:57 into the second period for a 2-0 lead.

But Blaz Gregorc lifted Slovenia within 2-1 with 14:11 remaining and Mursak's late heroics spoiled the Americans' hopes. Two-time defending champion Canada opens Thursday against Switzerland, but coach Willie Desjardins sent a message to his team about playing harder.

"When the guys were trying to make the team, they were playing harder. Then once they made it they are worried about getting injured so there's a bit of a lull," he said. "Hopefully we will get back to the team that's ready to play hard." Other Thursday openers send Finland against Germany, Sweden against Norway and South Korea against the Czech Republic.