Bannan, 20, was the pick of the youngsters in a hugely inexperienced line-up. Midfielder Jonathan Hogg, 22, came in for his first start alongside Bannan in a bold gamble by Gerard Houllier, who had nine players missing through injury.
Fletcher, however, wasn't fooled.
"I saw these young Villa players in the reserves against us last season," he said. "I knew what they were capable of. Young players respond to occasions like this.
"We didn't go into the game thinking because they had unknown players we would be taking the points for granted.
"I watch our reserve matches regularly and Bannan scored a hat-trick against us earlier this season. Marc Albrighton was in their reserves last season.
"Barry is talented. He's playing in the Premier League with Villa. If he gets a run, his confidence should grow. Having seen him for Villa's reserves and with the Under 21s he has a bright future."