[EURO 2012 WRAP] Cristiano Ronaldo hit the post twice, bringing his total on the bad luck charts to four balls off the woodwork in four games, but he provided the winning touch with a header that he nodded off the ground and bounced over Petr Cech for the lone goal in Portugal's 1-0 win over the Czech Republic in Thursday's quarterfinal opener.

Ronaldo, whose two goals gave Portugal a 2-1 win over the Netherlands in the deciding group game, hit the post just before halftime after a sublime move to break free of his defender and again in second half when his free kick grazed the far post.

But just when it looked like the Portuguese would not rewarded for a dominating display in the second half -- they finished with a 20-2 edge in shots -- Ronaldo won the game with a flying header off Joao Moutinho's cross.

With three goals in his last two games, Ronaldo has silenced his critics who suggested he was unable to replicate for Portugal the form he had at Real Madrid.

"We had a lot of opportunities," he said. "The Czechs did not have any -- that's a great game."

The supporting cast of Raul Meireles, Nani and Moutinho also put in strong performances, raising Portuguese hopes that they could finally win a major championship.

"I think the chances [of reaching the final] are 50-50," said Ronaldo, "and we just have to believe in it."

Portugal will meet the Spain-France winner Wednesday in Donetsk in its fourth appearance in the European Championship semifinals.