He also extended an invitation to the President to visit New Zealand, which Mr Pena Nieto indicated he was likely to take up next month.
As far as the mutual admiration society was concerned, Mr Pena Nieto proved such a master of flattery that Mr Key must have wondered which country he was leading.
In Mr Pena Nieto's hands, New Zealand was a role model in international diplomacy and had a vigorous civil society. It had a wonderful landscape and respect for the environment. It was tolerant, pluralistic, had an inclusive society and a dynamic economy.
In return, Mr Key praised Mr Pena Nieto's ambition of bringing prosperity to Mexico and sympathised with his goal to push through reforms, including controversial changes to education which have outraged unions and prompted large protests.
"Like all leaders, we all have challenges, but I think Mexico will be in good hands under your leadership."
The setting for the opening was stunning, held in front of the dramatic Castillo de Chapultepec high above Mexico City. The meeting itself was held in a room with a sweeping Diego Riviera mural.
The military band charged with playing the national anthems even managed to make New Zealand's rather subdued anthem sound like a stirring call to nationhood.
Some sympathy was spared for the English to Spanish translator charged with translating Mr Key's address, accent and mumbles included. He did at least spare her from his infamous neologisms, now known as Key-ologisms.
The most entertainment was to be had from the name pronunciation - John Key became Junkay in Spanish - while his pronunciation of Mr Pena Nieto's wife's name Angelica as Anyalga also raised eyebrows.
At times Mr Key came across as the travelling salesman for the car yard of New Zealand. Addressing an audience of Mexican business people, he set out the case for investing in New Zealand, using the free-trade agreement with China as leverage.
Diplomatic Itinerary
* Prime Minister John Key will be in Bogota, Colombia this morning for his first meeting with President Juan Manuel Santos.
* His stop in Mexico included a speech to the Mexican Institute of International Affairs and a meeting with Mexican President Enrique Pena Nieto.
Announcements included:
* Both supported concluding Trans Pacific Partnership Agreement talks by the end of the year, and for it to be as comprehensive as possible.
* Mr Key invited Mr Pena Nieto to visit New Zealand.
* Mr Pena Nieto confirmed Mexico would support New Zealand's bid to get a non-permanent seat on the Security Council.
* Both countries would work on projects to increase trade and investment.
