TAMPA, Fla. — Freddy Adu scored on a penalty kick in the 42nd minute to help the United States' under-23 team beat Panama 1-0 tonight in the second round of Group A pool play in CONCACAF Olympic qualifying.

The Americans, coming off a 1-1 tie with Cuba on Tuesday, improved to 1-0-1, while Panama dropped to 0-2. The top two teams in the group will advance to the March 20 semifinals in Nashville, Tenn., along with the top two from Group B. The finalists will earn spots in the Beijing Olympics.

The United States will finish group play Saturday against Honduras (2-0). Panama, which cannot advance, will play Cuba (0-1-1) on Saturday. If Cuba loses or ties, the U.S. automatically advances. Honduras already has clinched a spot in the semifinals.

Adu scored after Panama goalkeeper Jose Calderon received a yellow card for tripping Josmer Altidore 15 yards from the goal during a breakaway scoring chance. On his penalty kick, Adu struck the ball with his left foot, and it went just past Calderon's outstretched arms into the right side of the net.

The 18-year-old American star also scored against Cuba.

The United States again had trouble converting scoring chances into goals. In the 47th minute, Calderon hit the ground to knock a shot away. Later, he stopped Holden Stuart's free kick from 25 yards.

The United States had a brief scare in the 56th minute when Adu fell to the ground after making contact with a Panamanian player. But just as Adu was about to be placed on a stretcher, he bounced up off the ground and was playing again moments later.