Goals from Franculino Dju, Mama Balde and Alvaro Djalo helped the Djurtus subdue the West Africans in the tough clash.
Lawal expressed his frustration with Nigeria's performance as the defeat left Eric Chelle's side three points behind Guinea-Bissau in Group L after two qualifying matches.
“I expected the team to take the game straight to their hosts, but we allowed them to dominate and created very few chances to threaten their goalkeeper,” he told Complesports.
“I really feel disappointed with this result, but that is not the end of the world because there are still many matches to play in the group. I am still optimistic the Super Eagles will top the group.”
