ATLANTA - A night of conflict and controversy ended with referees surrounded by security and another win by Mexico surrounded by suspicion.

Andres Guardado scored two goals on penalty kicks, including the tiebreaker in extra time, and six-time champion Mexico beat short-handed and angered Panama 2-1 in the Gold Cup semifinals Wednesday night.

Turmoil on the field incited fans — among the 70,511 at the Georgia Dome — to hurl drinks and other debris onto the field on two occasions.

Tensions rose after a foul was called on Panama's Roman Torres for touching the ball with his hand in the penalty area late in the second half when Panama was protecting a 1-0 lead. There was a delay as cups were thrown from the stands. Players from both teams argued on the sideline and appeared to be on the verge of an all-out melee before being separated.

The call set up Guardado's first penalty kick in stoppage time.

Panama coach Hernan Gomez called it a "stolen goal" and said he was left with "immense sadness."

"I ask myself why did this happen?" Gomez said through a translator. "We were doing everything well. It is very sad.

"We are people of football and I still can't believe this happened and I wonder if this really happened."

Mexico will play Jamaica in the final Sunday in Philadelphia. Jamaica upset defending champion United States 2-1 in the first semifinal and will be appearing in its first final.

"This is not the ideal situation," Mexico coach Miguel Herrera said. "It wasn't the ideal way to win."

Panama's Roman Torres scored on a header early in the second half, and the 1-0 lead held until Guardado's penalty kick in stoppage time. The penalty kick, which followed a 10-minute delay as tempers flared, set up the extra time.

Panama played at a disadvantage after forward Luis Tejada drew a red card and was ejected for his contact with Mexico's Francisco Rodriguez about 25 minutes into the match.

Similar controversy surrounded Mexico's 1-0 win over Costa Rica in the quarterfinals Sunday night. The win came on Guardado's penalty kick in the final minute of extra time after Roy Miller was called for a questionable foul on Oribe Peralta.

"We didn't produce football," Herrera said. "We had nothing to do with that."

Panama was denied its second straight final. It lost to the U.S. in the 2013 final after beating Mexico in the semifinals.

A win by Panama's win would have been an upset, but not on the level of Jamaica's shocker over the U.S. Mexico is No. 40 in the world rankings and has appeared in seven of 12 finals in the CONCACAF tournament. Panama is 62nd.

A header by Torres early in the second half broke the scoreless tie. Torres was in position to intercept a corner kick from Erick Davis in front of the goal, and his header to the ground bounced past goal keeper Guillermo Ochoa.

Torres jumped in glee, his fists clinched, as Panama took its fifth straight 1-0 lead in the tournament. In each of its first four games, Panama took 1-0 leads only to allow the equalizer. This time, its defence held firm.

In the 25th minute, Tejada jumped to attempt a header when he hit Rodriguez with his arm and hand, knocking the defender to the ground. Tejada protested and had to be restrained by his teammates when the red card was pulled.

There was tension from both teams as Mexico players pushed Panama's players away from Rodriguez, who remained on the ground. Tejada was very slow to leave the field, stopping and circling back as fans hurled cups and plastic bottles in his direction. Tejada's teammate Adolfo Machado attempted to serve as an escort off the field but finally gave up when Tejada continued to linger.

Finally, Tejada departed into the tunnel, leaving Panama with the difficult task of taking on Mexico with 10 players.

Mexico's Miguel Layun cleared the debris from the field, picking up the cups and bottles, so play could resume.