Samuel Wilson's pair of goals, one in each half, gave Nicaragua fifth place in the Central American Nations Cup, matching its best performance achieved previously in 2005.
The loss left Guatemala in sixth place in the Copa de Naciones Digicel de UNCAF, a title it won eight years ago and a tournament it had never finished worse than third. It did not enter the 1993 championship.
Nicaragua had never beaten Guatemala in 16 previous tries, earning one draw - in 1986 in a friendly -- and losing the other 15 times.
Wilson's diving header inside the near post put Nicaragua ahead in the 39th and a right-footed roller to the far post sealed the game in the 85th. He celebrated the second goal with a shirt-peeling exhibition and subsequent yellow card.
"It's as if we were going to a World Cup," Nicaragua manager Otoniel Olivas said.
Los Pinoleros, which opened the tournament with a shocking 1-1 draw against El Salvador, join los Cuscatlecos, Costa Rica, Honduras and Panama as Central America's qualifiers to the Gold Cup.
Nicaragua is the last team in the field that also will feature Canada, Mexico and the United States from the North Zone, and Jamaica, Grenada, Guadeloupe and Cuba from the Caribbean.
