Bayern romped to the top of Group F in the Champions League as Dinamo's 45-match unbeaten run was halted in emphatic fashion.
Lewandowski again ran riot at the Allianz Arena as Mario Goetze and Douglas Costa also netted to put Bayern top of their group following their 3-0 win at Olympiakos a fortnight ago before they face Arsenal away in three weeks.
Poland hot-shot Lewandowski has now scored 10 goals in his last three games after netting five in just nine spectacular minutes of Bayern's 5-1 hammering of Wolfsburg last Tuesday before claiming two more in Saturday's 3-0 win at Mainz.
Bayern host Borussia Dortmund on Sunday in a top-of-the table clash in the Bundesliga, but their Spanish head coach said they can enjoy a few beers at Munich's annual bumper beer festival before focusing on their next match.
The Spaniard put Lewandowski's success down to the width on Bayern's game from fleet-footed wingers Costa and Kingsley Coman.
"That was a good team performance over the whole 90 minutes," said Guardiola.
"Six points means we're on the right path. Tomorrow we're off to Oktoberfest, after that we'll have time to think about Dortmund.
"With Douglas Costa and Kingsley Coman our playing style is much better, we can play out wide more and the strikers have more chances.
"Even our counter-attack game was very good."
Bayern captain Philipp Lahm said the game was over after 30 minutes as the hosts took a 4-0 lead against a woeful Zagreb team, whose defence capitulated in their first defeat since November 2014.
"We played in a very concentrated fashion from the start and when you take your goal chances, the game was over after 30 minutes," said Lahm.
Lewandowski, the Bundesliga's top scorer, will be hoping to add to his tally against ex-club Dortmund on Sunday.
"I am happy to get three more goals, but the main thing is that we won 5-0," said Lewandowski.
"It doesn't matter how many goals I score as long as we keep picking up points.
"The whole team played well, which creates opportunities for me."
But with 10 goals in eight days, Lewandowski is in incredible form.
"He's had an unbelievable week behind him," admitted Lahm, who joked that he expects at least three goals from Lewandowski per game from now on.
Olympiakos' shock 3-2 win at bottom side Arsenal means Zagreb drop to third in the group and Dinamo's coach Zoran Mamic admitted his side was outplayed.
"Bayern have showed how strong they are and we caught them on a very good day, they were better than us in all departments," said Mamic as his side suffered their heaviest away defeat in Europe.
"The difference in quality was huge and we were brutally punished.
"They have a lot of good players, they are all fast, and it's hard to commit tactical fouls against them.
"They deserved to win by that margin."