The French forward was dropped to the bench for Saturday's game at Vicarage Road after being substituted during the 1-1 home draw against Peterborough in the previous match.
But the 22-year-old stepped off the bench to score a superb stoppage-time goal to salvage a 3-3 draw and a point for City after they had thrown away a two-goal lead.
"The gaffer [Nigel Pearson] did not think I did too well against Peterborough and took me off," N'Guessan told the Leicester Mercury.
"But I think I did well and scored so I hope he thinks of me at the weekend when we play Preston. The goal will give me more confidence."