The Londoners failed to satisfy their American fans as City, days after launching a Major League Soccer franchise in New York, showed a determination to make their mark in the Big Apple.
A well-taken double by Samir Nasri and further goals from Gareth Barry, James Milner and Edin Dzeko secured victory but Chelsea contributed to an entertaining encounter with a Ramires double and Juan Mata's free-kick.
The final whistle brought to an end Napoli-linked Benitez's tenure as interim boss.
The club were unwilling to comment on reports that Jose Mourinho, who is leaving Real Madrid this summer, has already agreed a deal to return to Stamford Bridge for a second spell.
As they had in the meeting between the two clubs in St Louis on Thursday, Chelsea had the majority of the support in the 39,462 crowd at one of baseball's most famous venues.
That was clear evidence of the progress they have made in the US in recent years and what City must hope to emulate.
Chants of "Let's go Chelsea", however, indicated they were playing to a different sort of support than back home.
City began with purpose, as if well aware of the importance of selling themselves to their audience.
They attacked with vigour and their passing was slick, and with the aid of some poor Chelsea defending, they were ahead inside four minutes.
Oscar gave the ball away to Sergio Aguero and although Hilario palmed away his shot, Barry was on hand to tap in.
They could have been 3-0 up inside six minutes as Sergio Aguero narrowly failed to connect with an Aleksandar Kolarov cross and Pablo Zabaleta shot at Hilario.
Chelsea wanted a penalty when Fernando Torres went down under a Dedryck Boyata challenge but the tackle was clean and Demba Ba thought he had scored - as did thousands of fans - when his shot hit the side-netting.
City got their second when Nasri lobbed Hilario from a Milner pass.
Torres had an effort from a corner disallowed because a second ball was on the pitch and Joe Hart palmed the retaken corner onto the bar.
Aguero and David Luiz were involved in a controversial clash in last month's FA Cup semi-final and it seemed needle remained with an argument before the break that continued as the players walked off.
Chelsea pulled a goal back within a minute of the restart as Ramires raced onto a long ball from Luiz to score.
Ramires then had a deflected effort cleared off the line by Milner, who struck at the other end after combining with Dzeko.
Dzeko was again involved as Nasri grabbed the fourth with a neat dink. Mata gave fans hope of a comeback with a superb free-kick eight minutes from time but Dzeko rifled one in from long range and almost beat substitute Petr Cech again moments later.
Source: Manchester City MAD