Daniel Alves, one of only five members of the World Cup squad who played on Thursday, opened the scoring in Brazil's second game since their World Cup failure.
Pato got the second midway through the second half and Nilmar added the third in stoppage time.
Menezes replaced Dunga following Brazil's quarter-final exit at the World Cup and has already shown his intention to replace his predecessor's pragmatic and unpopular counter-attacking game with a more free-flowing style.
In their first outing under Menezes in August, Brazil produced an entertaining 2-0 win over the United States with Pato scoring his first international goal for two years.
Brazil, who gave a debut to 18-year-old Philippe Coutinho, had a lucky escape at the start when Iran forward Mohammad Gholami had the ball in their net only to see his effort disallowed for offside.
Having survived that, the 2014 World Cup hosts went ahead with an Alves free-kick that went in off a post in the 14th minute.
Brazil took control and should have increased their lead when captain Robinho's shot hit the crossbar and Pato fired over from the rebound when it looked easier to score.
Brazil, whose next outing is against Ukraine in England on Monday, gave debuts to defender Rever and midfielders Wesley, Elias and Giuliano as Menezes shuffled his team at half-time.
But they nearly conceded an equaliser when Javad Nekounam struck the post just after the break.
Pato was guilty of more misses as Brazil regained control but the AC Milan player finally hit the target in the 69th minute after latching on to an Elias pass.
Substitute Nilmar completed the scoring when he turned in a cross by Andre Santos.
