Mazzarri feared his side would be humiliated by the Bundesliga giants but they produced a late winner to earn a morale-boosting victory.

Napoli recovered from David Alaba's early goal to move ahead courtesy of strikes from Paolo Cannavaro and Goran Pandev, only to see Xherdan Shaqiri level matters once more with a free-kick.

However, Lorenzo Insigne then popped up with a late winner for the Coppa Italia holders, much to the delight of Mazzarri.

"We played an excellent game against the Champions League runners-up," the 50-year-old told Corriere dello Sport.

 "We did well in two areas: giving away little and creating a lot.

"I'm very happy as I did not expect this performance against a team that is much further ahead of us in their pre-season preparations. Indeed, I even thought there was a risk of them making a show of us!"

Mazzarri was particularly pleased with the performance of Eduardo Vargas, who has struggled to find form since arriving at the San Paolo during the January transfer window from Universidad de Chile.

"He needed to do a pre-season with us and today he played well and deserved a goal," the Tuscan coach said.

"Insigne also had an excellent showing."

Meanwhile, Bayern coach Jupp Heynckes felt that there were plenty of positives for him to draw from the match.

"I'm happy with the way my team played for long spells," he told his club's official website.

"That was a good and valuable test, which tells you a lot more than when you play a team and beat them 11-0."