Marcus Bent replied for Ipswich but their recent revival came to an abrupt end at the hands of rampant City.
After the game Pearce told the BBC: "He puts confidence in players - people want to play for him.
"Whoever's come in this season has enhanced the team.
"Ipswich allow you to play because they are a good footballing side and I thought we knocked it around well today.
"We're doing okay at the moment, our priority is the league, but it's nice to stay in the cup."
City now face a trip up to Newcastle in the fifth round, which means a return to St James' Park for Keegan and Pearce.
“We have got one or two connections obviously – the manager being the main connection,” Pearce continued. “I am sure he will love going up to Newcastle – the ovation he will get up there.”