One of those midfielders, 18-year-old Renato Sanches, combined with Nani to create the Portuguese equaliser in the 33rd minute.
Five minutes from the end of the 90, Ronaldo had the best chance of the second half, but the Real Madrid star could only kick thin air when trying to guide home a dropping ball from 10 yards out.
His performance against Croatia was such that he was handed his first start of the tournament in the quarter-final against Poland on Thursday night in Marseille, where Sanches wrote history.
As the clock ticked over the 100-minute mark, Lewandowski rolled a attractive ball across the six-yard box, but Milik couldn't get there in time to apply a close-range finish, before the Seleccao answered in the form of Nani firing straight down Fabianski's throat. Looking like a veteran Sanches drove the ball into the top left corner for the goal.
The Real Madrid star should have had a penalty on the half-hour when he was pushed over by Michal Pazdan but referee Felix Brych waved play on.
Extra-time games played by Portugal at the European Championship - only the Netherlands (7) have played more.
"We've done our fans proud and it's a good start to build on for this team".
"I'm confident about my work". We are in the semis and go on from here. "I'm happy to be man of the match again, but the individual comes after the team", said Sanches, who also scored the second shootout penalty.
But Portugal worked their way back into the game and Cristiano Ronaldo, who had seen a volley blocked, hit a free-kick from 40 yards straight into the wall.
"It doesn't matter that he (Blaszczykowski) missed his kick, he's still a great player and a big friend", said defender Kamil Glik, who is moving from Serie A's Torino to French side Monaco. "People always focus on Cristiano and say that he has to score". But we did well, we played on the front foot and had the better chances, even if Poland had a few as well. Renato is still growing, he'll have to take all his qualities, put it all on the pitch and it's my job to help him.
Cristiano Ronaldo moved closer to his "dream" of finally landing Portugal a major worldwide title after squeezing past Poland 5-3 on penalties in Marseille.
He converted in nerveless style as Portugal came out 5-3 winners from the spot to book their place in the semi-finals for the second tournament running.
Portugal's Rui Patricio saves from Poland's Jakub Blaszczykowski during the penalty shootout.