Simeon Alexander Jackson of Canada (C) feels the pressure   Panama have ended the United States\' 26-game unbeaten run in group play at the Gold Cup, downing the US 2-1 to book a quarter-final berth in the regional football championship .
Luis Tejada scored in the 19th minute and Gabriel Gomez converted a penalty in the 36th for Panama, who posted their first victory in nine meetings with a US side that had never lost a match in the group stage of any Gold Cup.
Clarence Goodson pulled a goal back for the Americans in the 67th minute. But at the end of the night, Panama topped Group C with six points followed by the United States and Canada both on three.
The United States can still reach the knockout stage, with the top two teams from each of the three groups assured of quarter-final spots.
In the day\'s other Group C encounter, Dwayne De Rosario\'s penalty in the 51st minute gave Canada a 1-0 victory over 10-man Guadeloupe.
De Rosario beat goalkeeper Franck Grandel after Stephane Zubar brought down Ali Gerba in the penalty area.
Guadeloupe had been a man down since the fourth minute, when Jean-Luc Lambourde received a red card for his tackle on Canada\'s Will Johnson.
Group C action will conclude in Kansas City on Tuesday, when the United States wil face Guadeloupe and Canada play Panama.
With the victory over Guadeloupe, Canada also preserved their hopes of advancing. In addition to the top two from each group, the two best third-placed teams go through.
The tournament to crown the North and Central America and Caribbean region champion continues on Sunday when Group A pool play concludes in Chicago.
Mexico, already assured of a quarter-finals berth despite a drugs dust-up, will face Costa Rica while El Salvador takes on Cuba. Mexico lead the group with six points to Costa Rica\'s four.
Mexico, the reigning Gold Cup champions, were left with 17 players after goalkeeper Guillermo Ochoa, defenders Francisco Rodriguez and Edgar Duenas, and midfielders Christian Bermudez and Antonio Naelson \"Sinha\" were removed from the team Thursday by Mexican football authorities after testing positive for clenbuterol.
The Mexican federation has blamed the positive tests at a pre-tournament training camp near Mexico City on tainted meat and asked to replace the players.
CONCACAF officials have said they need more information before they decide.
\"It\'s a very unfortunate situation, but we need to look forward,\" Mexico star Javier \"Chicharito\" Hernandez said Saturday after his team trained at Chicago\'s Soldier Field. \"Right now, the most important thing is Costa Rica.\"
The Gold Cup winners secure a berth in the 2013 FIFA Confederations Cup.