“It was about time we won one, we deserve it,” said Casillas, who saved from Daniele De Rossi and Antonio Di Natale.
“Losing on penalties again would have been terrible. Now the fans can enjoy this because we’ve got to the semifinals at last.”
The game ended goalless after extra time as both well-organized defenses coped relatively comfortably with the too-cautious attempts to break them down.
“It was a very evenly balanced game,” said Spain coach Luis Aragones. “Italy is always a difficult side to break down and very dangerous on the break.”
Two years ago Italy won the World Cup on penalties and current coach Roberto Donadoni had no complaints Sunday.
“The players should leave here with their heads held high,” he said after they took their tally of shootout defeats to five.
Spain is the only one of the Euro 2008 group winners to reach the semifinals after Portugal, Croatia and Netherlands all lost.
Like the three which fell before them, the side was unable to reproduce its earlier form as the team was frustrated by an Italy side, which had rediscovered its defensive solidity after a shaky start to the tournament.
Neither keeper was stretched in the first half and though Spain continued to have the better of the game after the break its play lacked accuracy and a real commitment to attack.
Fabregas and Santi Cazorla came on after an hour and though they livened things up a little it was Italy substitute Mauro Camoranesi who almost opened the scoring moments later when his close-range shot was saved by Casillas with his feet.
Midfielder Marcos Senna then almost snatched it for Spain nine minutes from time when Gianluigi Buffon fumbled a long-range Marcos Senna drive on to a post but he safely gathered the rebound.
Spain remained the more ambitious side in extra time but few in the crowd were surprised when it went to penalties.
Buffon saved from Daniel Guiza but David Villa, Santi Cazorla and Senna all beat him and after Casillas played his part with two diving stops, Fabregas settled it.
“Naturally, it was the most important goal of my life,” said Fabregas. “It was football justice that we won the match.”
(SD-Agencies)