Panama’s Justin Simons was ejected for a foul that injured Tyler Adams, giving the USA a man-advantage for 72 minutes, but Los Caneleros took a 37th minute lead with a shot by Leandro Ávila that deflected off defender Marlon Fossey and beat goalkeeper Jonathan Klinsmann.
Jeremy Ebobisse hit the crossbar with a header in the 48th minute and Panama, runner-up to Mexico at the 2015 Concacaf U-20 Championship, held on for the win while out-shooting the USA 10 to nine.
The game was the first of the USA’s three matches in Group B, from which the top two finishers advance to the second phase. Coach Tab Ramos’ team faces Haiti, a 5-1 winner over St. Kitts and Nevis, on Tuesday.
Panama also beat the USA in group play two years in a different format. The 12-team tournament consisted two groups of six with the group winners qualifying for the World Cup and the second- and third-place teams advancing to single-game playoffs to determine the other two teams that would advance.
The USA finished in its group two years ago and will need to finish in the top two in Costa Rica to stay alive. The second phase this time involves two groups of three teams with the top two in each group qualifying for the world championship in South Korea.
Feb. 18 in Tibas, Costa
USA 0 Panama 1
Goal: L.Avila (Córdoba) 37.
USA -- Klinsmann; Fossey, Redding (Williamson, 69), Glad, Acosta; Lennon, Palmer-Brown, De La Torre (Craft, 69), Saucedo; Ebobisse, Adams (Sabbi, 31)
Panama -- Taylor; Vergara (Gutiérrez, 93+), Rivera, Ramos, Andrade; Simons, R.Avila, Tejada, L.Avila (Hinestroza, 79); Martínez (Jaen, 72), Córdoba.
Shots on Goal: 2/2
Corner Kicks: 6/5
PAN - Justin Simons (ejection) 18
USA - Luca de la Torre (caution) 41
PAN - Cristian Martínez (caution) 46+
USA - Sebastian Saucedo (caution) 74