Brazilian striker Denilson, who scored all Pohang's goals in normal play in the tournament, netted his fourth in three games three minutes before halftime to put the Asian champions ahead.
Atlante midfielder Jose Guerrero allowed a cross from the left to bounce instead of clearing first time and midfielder Shin Hyung-min headed it into the middle where Denilson's shot left keeper Federico Vilar with no chance.
Atlante equalised from the restart. Midfielder Gabriel Pereyra hit a fine pass through to striker Rafael Marquez on the right and he steered a low shot in off the far post.
Jose Cruz, the Atlante coach, had sent on Brazilian striker Lucas Silva for midfielder Daniel Arreola and asked Pereyra to play higher, closer to Marquez.
The CONCACAF champions had the better of the second half but failed to put away several good chances.
PEREYRA CLOSE
Argentine Pereyra hit the woodwork three times in the match.
In a flurry of action in the 12th minute, Vilar saved a searing shot from Shin. Atlante immediately counter-attacked with Christian Bermudez's lob just being touched away by Song and Pereyra headed the corner on to the bar.
Denilson went on a solo run from halfway in the 20th minute, racing past four defenders, but Vilar saved his shot.
Atlante right back Fernando Navarro did a one-two with Marquez and Song, one of four changes in the Pohang side after their had three men sent off in the 2-1 semi-final defeat by Estudiantes of Argentina, saved his shot with his left foot.
Just past the half hour, Pereyra hit the post with a low left-footed strike.
Song blocked a gilt-edged Silva chance on the hour, Pereyra hit the post again following an Atlante free-kick and Vilar saved a point-blank effort from Denilson in stoppage time.
No extra time was played.
