Clint Dempsey and the United States are at a loss against Panama in Tampa. Panama won, 2-1. (J. Meric/GETTY IMAGES)

Luis Tejada scored in the 19th minute, Gabriel Gomez converted a penalty kick later in the first half and Panama stunned the United States, 2-1, on Saturday night in Tampa to advance to the quarterfinals of the Gold Cup.

The victory was the first for the Panamanians in nine meetings with the Americans.

Meantime, the United States had not lost a match in the group stage of any Gold Cup.

“Sometimes you just come out flat for whatever reason. At this level, and against a good team, you can’t do that,” U.S. star Landon Donovan said. “Some nights you come out flat and you don’t get punished, but other nights you do. We learned a valuable lesson.”

Despite the loss, the U.S. can clinch a spot in the quarterfinals by beating Guadaloupe in its final Group C stage match Tuesday night in Kansas City.

Tejada finished a sequence that began with Nelson Barahona’s free kick when he tapped in a rebound after U.S. goalkeeper Tim Howard lunged to get a hand on Armando Cooper’s header from left of the net. American Tim Ream’s foul set up Gomez’s penalty kick, which the Panamanian lifted over the diving Howard for a 2-0 lead in the 36th minute.

Clarence Goodson gave the U.S. hope for a dramatic comeback with a goal in the 68th minute. The Americans had a couple of opportunities to pull even.

But Chris Wondolowski missed a wide-open net in the 80th minute and Jaime Penedo made two of his six saves in injury time. Panama Coach Julio Dely Valdes said through a translator that the victory was especially gratifying because of the effort that went into finally getting over the hump against the Americans.

“We worked very hard for it,” the coach said. “I’m absolutely happy because we made history.”

The loss was just the second for the Americans in their past 21 Gold Cup games. They had been 6-0-2 against Panama, with all the meetings coming in either Gold Cup or World Cup qualifying.

Despite defeating Panama in the past three Gold Cups, the Americans stressed they could not overlook the Panamanians because each of those games had been close.

The teams played to a scoreless draw in the 2005 final, with the U.S. winning a penalty shootout to take the championship. They met in the quarterfinals in 2007 and 2009, with Panama losing, 2-1, each time.

“In the first half as the game was developing, we had the ball a lot but we weren’t able to take advantage of some situations,” U.S. Coach Bob Bradley said.

l  CANADA 1, GUADELOUPE 0: Dwayne De Rosario scored on an early second-half penalty kick to lead Canada past Guadeloupe, 1-0, in a Group C CONCACAF Gold Cup match on Saturday night in Tampa .

De Rosario beat goalkeeper Franck Grandel in the 51st minute after Stephane Zubar was given a yellow card for bringing down Ali Gerba in the penalty area.

“I was very fortunate to put the penalty shot in and create a victory for us,” De Rosario said.

Jean-Luc Lambourde put Guadeloupe at a disadvantage during the fourth minute when he received a red card following a lunging tackle on Canada’s Will Johnson.

“We didn’t want to change what we set out to do . . . just be patient,” Canada Coach Stephen Hart said. “It was very, very hot. Make them run. Keep the ball moving and just be careful not to get caught on the counter-attack.”

Real Salt Lake, Union tie

Fabian Espindola scored in the 53rd minute to help visiting Real Salt Lake tie Philadelphia, 1-1, in MLS. Keon Daniel scored his first career goal for Philadelphia after he headed a cross from Michael Farfan past goalkeeper Nick Rimando in the 24th minute. Philadelphia remained unbeaten at home (4-0-3).

l  DYNAMO 2, CHIVAS USA 1: Host Houston took advantage of an own goal in the 55th minute. The deciding goal came off Brad Davis’s corner kick. Michael Lahoud hit the ball out of the goal mouth, but it pinballed off Chivas USA’s Heath Pearce and into his own goal.

“I’m happy we won,” Houston Coach Dominic Kinnear said. “It’s been awhile. Give the guys credit for coming out of halftime determined.”