Portugal are hitting form at just the right time and have now scored six in three games as their attacking intent proved too much for a defensive Czech Republic who barely threatened their opponents goals.
Portugal started slowly but once they hit their attacking stride the Czech’s had no answer to Ronaldo and his trickery.
The first half ended with Portugal gradually pushing the Czech’s back into their own half and just before the break a brilliant piece of skill from Ronaldo saw him bring the ball down, turn, then fire a shot against the base of the post.
The second-half continued in much the same way with Portugal camped in the Czech’s half as Ronaldo ran their defence ragged, but it was substitute Almeida who had the first chance but headed over the Czech crossbar a feat he was to repeat later.
Ronaldo again hit the woodwork and Petr Cech was forced to make a couple of smart saves to keep the Czech Republic in the game.
But finally with 11 minutes remaining the Czech rearguard was breached as Felipe Moutinho burst into the penalty area, crossed into the middle for the darting Ronaldo to head down and powerfully past Cech.
Portugal could have settled the game as further chances were created but in the end comfortably saw out time and book a place against Spain or France in the semi-finals.
Referee: Howard Webb (ENG)
Venue: National Stadium, Warsaw
Czech Rep scorers:
Portugal scorers: Ronaldo 79
Yellow cards: Veloso (POR), Nani (POR), Limbersky (CZE)