Pena Nieto on Thursday thanked the 126 Olympic and 66 Paralympic athletes for their dedication and hard work, reports Xinhua
At the event, which was preponed due to Pena Nieto's trip to the United States, the president handed the national flag to the selected flag bearer, and called on the athletes to do their best.
"You will be going to compete, to make Mexico proud, to show capability and send a message of peace, harmony and solidarity with all of the countries that will be represented at Rio," Pena Nieto said.
The head of Mexico's National Commission for Physical Culture and Sport (Conade), Alfredo Castillo, said this year's 126-member Olympic delegation was the largest in 40 years.
Castillo said the field of sports in Mexico was undergoing renovation spurred by a recent push to combat corruption among the different federations that received government funding, but had little to show for it.
In an apparent response to critics who said Mexico had historically underperformed at the Olympics, Castillo called for patience, and pointed to China as a country that gradually grew into an Olympic powerhouse.
"China got five gold medals in 1988. At the 2008 Beijing Games, 20 years later, China got 51 gold medals. That entails a process of five Olympic Games, where doing things in a professional manner got results," said Castillo.
"An athlete is not built in a day, it takes many years of effort and sacrifice," added Castilllo.
Taekwondo athlete Maria del Rosario Espinoza stressed the importance of having the public's support to motivate the competitors."We want to feel supported, to feel the support of 100 million Mexicans," said Espinoza, adding "we are all going after the goal, which is Olympic glory."
According to the Mexican Olympic Committee (COM), Mexico's delegation is comprised of 81 men and 45 women who will take part in a total of 76 different competitive events.
The Rio Olympic Games open on August 5.