Justin Faulk of the Carolina Hurricanes scored four minutes into overtime for his second goal of the game Friday, sending the United States to a 3-2 victory over Kazakhstan at hockey's world championships.
In Group B, Canada beat defending champion Finland 5-3 in its toughest game yet at the tournament.
The Americans were coming off a 5-3 victory over Belarus on Thursday and improved to 3-1-1 in Group A.
Tampa Bay Lightning forward J.T. Brown opened the scoring 4:12 into the second period. Kazakhstan's Konstantin Pushkaryov tied it four minutes later on a power play.
Faulk scored his first goal 4:58 into the third period to make it 2-1, with Talgat Zhailauov evening the score 11 minutes later.
Canada twice overcame two-goal deficits in improving its record to 4-0-1 and taking over first place in Group H.
The winning goal came from Evander Kane of the Winnipeg Jets a little more than six minutes into the third period. He took a pass from linemate Corey Perry of Anaheim and beat Kari Lehtonen with a quick shot. Alex Burrows of Vancouver, John Tavares of the New York Islanders, Jeff Skinner of Carolina and Jordan Eberle of Edmonton also scored for Canada.
Antti Pihlstrom, Mikko Koivu of the Minnesota and Jussi Jokinen of Carolina had goals for Finland (4-1-0).