0959 GMT December 12, 2017
Pepe had a goal disallowed for offside after a referral to the video assistant referees before Ricardo Quaresma sold the keeper a dummy and slotted in, BBC reported.
Javier Hernandez equalized with a low header from Carlos Vela's cross.
Cedric Soares' 86th-minute shot was deflected in, but Hector Moreno snatched a point in the 91st minute.
Mexico defender Moreno, who recently joined Italian side Roma from Dutch club PSV Eindhoven, headed in off the post from a Jonathan dos Santos cross.
Earlier, Ronaldo had a header brilliantly tipped away by Mexico keeper Guillermo Ochoa, while Gelson Martins – a target for Liverpool – fired just wide on the counter for Portugal.
Portugal captain, Ronaldo lamented his side's failure to close out victory over Mexico after conceding an injury-time equalizer.
"It's not the result that we wanted. Our team practically had the match won and we conceded a goal in the final minutes. That's football though," Ronaldo told FIFA TV. "If we win (our next game) we'll be close to qualifying so it's not the time to sound the alarm."
Later on Sunday, Chile beat Cameroon 2-0 thanks to goals from Bayern Munich midfielder Arturo Vidal and Tigres forward Eduardo Vargas.
Arsenal forward Alexis Sanchez came off the bench to cross for Vidal's 81st-minute header, with Vargas finishing in injury time after Sanchez rounded the keeper but failed to beat a defender on the line.
Had Sanchez found the net, he would have become Chile's all-time leading goal-scorer. He currently has 37 goals, level with former Lazio and Juventus striker Marcelo Salas, who retired in 2008.