The Euro 2016 winners kicked on again in the game's closing stages and Cedric netted with the help of a Hector Herrera deflection, but Moreno responded to earn a share of the spoils, with further talk of Ronaldo's uncertain club future sure to follow Portugal to their next match against Group A leaders Russian Federation.
Moreno made it 2-2 in the 90th minute off a corner for Mexico with a ideal header when the Portuguese thought they had won.
In Kazan hosted the second match of the eighth confederations Cup Portugal national team missed the victory over Mexico.
Portugal play hosts Russian Federation in Moscow on Wednesday, while Mexico take on New Zealand in Sochi. The action from Group A continues on Sunday (June 18) as Euro 2016 winners Portugal take on Mexico at the Kazan Arena in Kazan.
Portugal still went on to take the lead shortly afterwards, with Ronaldo setting up Ricardo Quaresma.More news: Johnson Controls International plc (JCI)
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We look at the contribution of the 32-year-old, who is in the spotlight after appearing determined to quit Real Madrid and Spain over his unhappiness at a tax investigation.
Forward Nani scored but a review by video assistants showed a Portugal player was offside in the build up to the goal.
'It was not the result we wanted, the team had nearly won and we suffered in the last minute, but this is football, ' he said. "I think that we communicate well and we have a good understanding, and that leads to these good results".
But with the 90 minutes up, Mexican defender Moreno rose highest from the final corner of the game to head in the equaliser.
Dropping his shoulder to send goalkeeper Guillermo Ochoa to ground, Quaresma rounded the stopper and slotted the ball into an empty Mexico goal. Chile is ranked fourth, but lacks the same tradition as Portugal and Mexico and has struggled in South American qualifying.