Tim Howard smothered a shot near the edge of the 6-yard box, but his American teammates couldn't clear the ball. It eventually bounced over to Canada's Ali Gerba, who was only a few feet from the goal.
Gerba struck a powerful volley, and Howard somehow recovered in time for another marvelous save.
''Howard was absolute magic,'' Canada coach Stephen Hart said. ''I almost clapped.''
Howard and the United States opened their Gold Cup schedule with a 2-0 win over Canada on Tuesday night.
The U.S. lost 4-0 to Spain in an exhibition game last weekend, but back among regional rivals, the Americans were very much in their element. All along, their focus has been on this tournament, which determines the champion of North and Central America and the Caribbean.
''Coming off the game against Spain, obviously, you got down a little bit,'' striker Jozy Altidore said. ''Now, we've just got to build on it, because it's only going to get harder from here.''
Altidore scored in the 15th minute and set up Clint Dempsey's goal in the 62nd. The Americans have never lost a group stage game at the Gold Cup. They'll play again in Group C on Saturday against Panama in Tampa, Fla.
Oguchi Onyewu was left out of the starting lineup for the Americans. Coach Bob Bradley went with Tim Ream and Clarence Goodson in central defense.
''We feel that it's a good combination,'' Bradley said. ''As we've gone through training, we feel like the balance between the two is good.''
After looking overmatched against Spain's smooth passing, the Americans didn't allow Canada any good chances inside the penalty area until Simeon Jackson dribbled past Ream and Carlos Bocanegra in the 57th minute. Ream was able to recover in time to prevent Jackson from getting a shot through to the goal.
When the Canadians did increase the pressure late in the game, Howard was ready. He reacted quickly to deflect Gerba's shot from the edge of the penalty area with his right hand in the 70th minute. About 15 minutes later, he made the two impressive stops seconds apart.
''At this level, whether it is the Premier League or an international, you aren't going to go a whole game without giving up chances,'' Howard said. ''Maybe in my son's rec league, but not here. They had one down the side and one on a goal-mouth scramble. That will happen.''
The Americans didn't field their best lineup in their loss to Spain, putting more emphasis on the Gold Cup. The tournament champion receives a berth in the 2013 Confederations Cup, an important World Cup tuneup.
The U.S. pressured Canada from the start. The 21-year-old Altidore, playing his first game at a Gold Cup, scored after running onto a long pass from Landon Donovan. Although Kevin McKenna was back to defend, Altidore was able to turn and take a low shot from a tough angle to the right of the goal. The ball slipped under goalkeeper Lars Hirschfeld and into the net.
There was little Hirschfeld could do about the second goal. Altidore sent a low cross to the right of the net, and Dempsey was able to knock the ball in while sliding across the grass near the far post. American Juan Agudelo was credited with an assist for deflecting the ball on its way to Dempsey, but it was Altidore who set up the play. He was named man of the match.
''For confidence, it was a good thing,'' Bradley said. ''The movement that led to the first goal and the cross to Dempsey for the second both were great plays.''
Shortly before the second goal, Dempsey nearly scored in even more spectacular fashion, back-heeling the ball while diving forward horizontally after Hirschfeld deflected a cross. The ball went out of bounds for a corner kick.
''I don't know what you would call that,'' Dempsey said. ''Maybe a squirrel kick.''
