While Mancini is expected to oversee a title challenge after another extravagant summer spending spree, Martinez is merely hoping for improvement after last season's narrow escape from relegation.
The clubs are close geographically but poles apart in terms of finances, squad strength and fanbase.
Yet for Martinez, whose side travel to the Etihad Stadium in the Barclays Premier League, all that is relative.
The Spaniard said: "Every club works with different objectives and different aims and that brings different expectations.
"I think it is fair to say Manchester City, since they won the FA Cup, have gone into a different status.
"They have shown already this season they are title challengers.
"They will be expected to have another fantastic season, but for us we are expecting to have another fantastic season.
"Our aims are completely different but I am extremely proud of the achievements of Wigan Athletic.
"The excitement is to try to improve on that over the next 10 months."
Wigan have made an encouraging start to the new Barclays Premier League season, claiming five points after draws with Norwich and Swansea and victory over QPR.
Yet those modest successes against the promoted clubs pale in comparison to City's storming start, which has seen them win three and score 12.
Martinez already expects this weekend's assignment to be one of his toughest of the season.
He said: "The change at Manchester City over the last three seasons has been phenomenal.
"They were a really solid side, very good in not conceding goals.
"Now all of a sudden they have gone a stage further, and they added a lot of firepower up front. They are a very well balanced team.
"Their performances this season - going to White Hart Lane with a real arrogance and being able to win the game in the manner they did (5-1) - shows their preparation mentally is completely different from where they were at the start of the last campaign.
"They are a completely different group of players now because they have the winning mentality.
"I think it is fair to say Eastlands is going to be one of the toughest places to visit this season."
City boast an embarrassment of attacking riches with the likes of Samir Nasri, Sergio Aguero, Carlos Tevez, David Silva, Edin Dzeko and Mario Balotelli in their squad.
Martinez admits watching them is exciting but is far from intimidated by the challenge of facing them.
He said: "Any team that fits so many world-class stars in is great to watch.
"It is not easy to get all that money and make it work but I think Roberto has managed it really well.
"He has a winning team ready to win major trophies and make history.
"We need to be ready for them. If we are perfect we can be competitive on the day and that is a really exciting challenge.
"I think we are ready to hit those levels."
Wigan were written off in many quarters last season before finally starting to turn positive performances into points in the closing weeks of the season to survive.
And Martinez, who signed three new players in Shaun Maloney, Albert Crusat and Patrick van Aanholt last week, wants to maintain the momentum.
He said: "I am really pleased with the way we have started this season, probably with the same intensity and competitive edge we finished the last campaign.
"That has been really important but it is very early days in the season.
"We have to work very hard on certain aspects to improve but the early signs have been really encouraging.
"Now we have got the three new faces, they have really brought something different to the squad.
"We are really excited about the whole month ahead, which is going to be really demanding. We need to be ready for it."
All three new players are in contention to make their debuts this weekend but defenders Steven Gohouri and Antolin Alcaraz remain out.