The Belarus midfielder believes the former Barcelona trainer's success was due to having a superior team to his rivals, and says he learned more from Arsene Wenger
The Belarus international, who played all 90 minutes of his side's recent shock 3-1 victory over Bayern Munich in the Champions League group stage, spent four years with the Catalan giants between 2008-2012.
"I learned more from Wenger than Guardiola, but Pep is a good coach," the 31-year-old told Esports en Xarxa.
"Guardiola is not the best coach in the world because he coached the best team in the world, with the best players, and that's why he won.
"It's hard not to win with a team like that and [Tito] Vilanova will have the greatest success.
"The best coaches in the world are [Jose] Mourinho, [Sir Alex] Ferguson and [Arsene] Wenger.
Hleb also spoke about his country's upcoming World Cup qualifying match with Spain on Friday.
"I will strive to do my best. Spain's team is almost unbeatable. They play brilliant football, like Barca," said the former Arsenal man.
Speaking on his time with the Blaugrana, the well-travelled star added:
"I was very ambitious and wanted to play more but Barca played each player for a certain amount of minutes.
"For me, that was not enough. I was angry and wanted more, which was why we had some conflicts with Guardiola, but now I understand it was the nonsense and tantrums of a little boy."