Adams refused to blame Defoe, who missed a penalty on the stroke of half-time which would have put Pompey 2-1 up.
The striker has now gone seven games without scoring and Adams added: "He's gone a few games now and needs a goal.
"It doesn't help when you miss penalties. He needs a goal.
"But he's a fantastic goalscorer and I'll keep faith in him. He always does something or creates a chance out of nothing."