Portugal defender Pepe thought he had opened the scoring in the 21st minute when he turned in a cross-shot after Ronaldo had smashed a shot against the crossbar, having blasted his initial free-kick into the defensive wall.
Southampton full-back Cedric Soares restored the Portugal advantage with four minutes left when his drilled effort looped in off Moreno. "But we are not anxious, there are two games left, we still have chances".
'It was not the result we wanted, the team had nearly won and we suffered in the last minutes, but this is football, ' said Ronaldo, who is under more scrutiny than usual playing for his country after it emerged on Friday he wants to quit Real Madrid and leave Spain as a result of an investigation into his tax affairs. As the game continued to play out, however, Portugal showed why they are in fact one of the better countries in the sport, as they looked more and more risky on the counter.
Ronaldo sprung the offside trap perfectly and drew in a couple of Mexican defenders to him near the edge of the box before deftly setting up Ricardo Quaresman for a simple finish in the 34th minute.
But Portugal's talisman was at his best in an action-packed first half in his team's opening match, with hosts Russian Federation and New Zealand still to come in the group.
"He is concentrating on playing for the national team and he wants to give the motivation to have a good tournament". We played without confidence, couldn't connect two or three passes.
Few players have succeeded alongside Ronaldo in Portugal's attack recently. Minutes after coming on, he almost scored a great headed goal but Ochoa came up with a terrific save.
Hector Moreno scored in added time to earn a point for the Mexicans five minutes after Cedric put the Portuguese in front. He, along with Nani and Ronaldo, are coming towards the last years of their career and it is hard to see how Portugal will adequately replace them after the 2018 World Cup.
Portugal, who are making their debut at the Confederations Cup, go into the clash with Mexico on the back of a convincing 3-0 World Cup qualifying win away against Latvia.