NASHVILLE, Tenn.(AP) -- The Americans showed they can attack and score in coach Caleb Porter's aggressive offense.

Now it's time for the U.S. U-23 men's national team to tighten up a few things.

And play more keepaway when it comes to the ball.

The Americans opened the CONCACAF Olympic qualifying tournament with a 6-0 win over Cuba on Thursday night, and they play Canada on Saturday night in the second of three games in Nashville, Tenn.

The top two teams in Group A advance to Kansas City, Kan., for the semifinals March 31, and the top two teams there qualify for London.

"We've got some dangerous guys in the attack," Porter said. "We've just got to make sure we continue to keep things tight defensively. That was for me probably the most disappointing. Obviously, we didn't give up a goal, but I thought they had a few more chances on counters ... We want to win the ball back."

El Salvador plays Cuba in the first of Saturday's doubleheader in this group of qualifying for North and Central America and the Carribean.

Canada played El Salvador to a 0-0 tie Thursday night, and the Americans might not be able to put on the show they did against Cuba. They had a 17-4 edge in goal attempts on Cuba along with outshooting Cuba 7-1. The Americans outshot Cuba 8-2 on corner kicks.

Joe Corona scored three goals in the game, while Juan Agudelo and Freddy Adu also added a goal apiece. The U.S. team even got an own goal off Cuba from midfielder Brek Shea's pass trying to find Agudelo in front of the net.

Porter also showed off an offensive tweak in having Shea and Adu switch sides, trying to take advantage of their strengths. Shea said that helps throw defenses off, something he thinks will help the U.S. team in the future create more scoring chances.

Adu said it worked pretty well with Cuba's left back following him everywhere he went.

"Once we switch it kinds of throws them off a little bit," Adu said. "I thought that we did a pretty good job in mixing it up and letting them think a little bit."

The Americans also had the advantage of Cuba playing a man down after Dairo Macias picked up a red card. Porter said they have a realistic perspective from the first game.

"Early stages, it wasn't as good as it needs to be moving forward," Porter said.

Porter's goal is sweeping all nine points possible in these three games in five days. That is why he substituted for Agudelo at the start of the second half with Teal Bunbury. Shea came off in the 57th minute with Joe Gyau getting into the game.

"We're going to be smart with how we manage our group from game to game," Porter said. "We're going to look at our team after each game and assess where we're at physically. Ultimately, we have to look at each game and try to get three points in each game and also be smart at how we manage the rigors of this difficult format."

Agudelo, who took an elbow from Macias in the mouth when the Cuban picked up the red card, said he was a little disappointed to come out at the half. But he said the key in preparing for Canada is making sure they get their legs back and play their style.

"If we play our game, we can beat any team," Agudelo said.

Even though the Americans started the scoring with Corona's first goal in the 11th minute, they didn't really loosen up the Cubans until late in the first half. Midfielder Mix Diskerud said they were lucky in some situations against Cuba and should have pressed higher and been more focused on defense.

"Moving forward, we're going to have more difficult games and we're just motivated to just do better every game," Diskerud said.

Canada coach Tony Fonseca is hoping his team got through the big hurdle of that opening game. He said his team didn't deal with the ball as well as they usually do against El Salvador, even though they did get a point. Saturday night's game will be a different challenge for the Canadians.

"The United States is physically strong, they have a lot of experienced players," Fonseca said. "They all have a lot going for them, they play at home, they will have all the support."

SI Apps
We've Got Apps Too
Get expert analysis, unrivaled access, and the award-winning storytelling only SI can provide - from Peter King, Tom Verducci, Lee Jenkins, Seth Davis, and more - delivered straight to you, along with up-to-the-minute news and live scores.