The world champions drew 1-1 with Paraguay and New Zealand in what had looked like an easy Group F and must now beat Slovakia on Thursday to guarantee a place in the last 16.
World Cup winner Pirlo, 31, missed the two games with a calf injury and is edging his way back to full fitness with coach Marcello Lippi cautious about his chances of starting.
"Pirlo is the great creative talent that Italy are missing," Bergomi, who played 81 times for Italy between 1982 and 1998, told Reuters.
"He has great experience, he is a player who has won a lot. He is never overawed by emotion. He is always very calm. He is a true leader of this team and when he has not been there, they have missed him a lot."
Sitting pensively at Italy's windswept yet sunny training ground in the rolling hills south of Pretoria, 1982 World Cup winner Bergomi watched Pirlo gingerly kicking a ball.
"If he can play he can really lend a hand but he shouldn't be rushed because with a calf injury it's a problem you have to be careful with," added the 46-year-old.
Famous for his distinctive accent and playing for only one club Inter Milan, Bergomi is sure where Italy's problems lie.
The Azzurri went 1-0 down to two goals following free kicks into the box in their first two draws and lacked verve up front.
"When you concede straight away like that from a dead ball it's never easy to hit back," Bergomi said.
"When you play against these teams that defend with a great physical strength, Italy at the moment are missing a little bit of brilliance especially up front, someone to skip past the last defender, to play that killer pass for the attackers to score."
Pirlo can play that perfect pass but has no great pace or trickery, unlike Antonio Cassano.
The Sampdoria man was among a number of forwards left out by Lippi and fans have begun to question the World Cup-winning coach's wisdom before he steps down for a second time after the tournament and hands the reins to Cesare Prandelli.
"The coach is right to say he has left no phenomenons at home because right now we can still qualify with a draw. There is still a big chance. Italy are stronger than Slovakia, we have the quality and motivation to win," Bergomi said.
"When results go wrong, everyone thinks they were right. We should respect the choices of the coach until the end."
