The Barcelona star headed home in the 87th minute to beat Czech Republic 1-0 in Toulouse and ensure his side claimed a deserved victory.
The defender's late effort lifted the frustration that had engulfed a Spanish side which dominated the Group D contest but toiled in the final third.
Petr Cech, who produced a number of impressive saves during the game, appeared to have almost single-handedly claimed a point for the Czechs.
But with three minutes remaining, Pique ghosted in at the far post to convert Andres Iniesta's cross.
"It was really important to start with three points," Pique said after the match. "Iniesta's pass was incredible.
"I think we played really well, we controlled the match but the ball looked like it didn't want to go in."
Two years on
Spain's victory provided a marked contrast to its last attempt at defending a major title.
Two years ago to this day, it began its World Cup campaign in Brazil -- a tournament which would begin and end in spectacular failure.
A 5-1 defeat by the Dutch in the opening game sent shockwaves through the world of football and extinguished its aura of invincibility.
Five days later Spain was beaten 2-0 by Chile
and was dumped out of the competition at the group stage -- the fifth champion to have suffered the fate.
Much introspection has taken place since and, while the more pessimistic of supporters might have feared more failure in France, Pique's late strike should at least give reason for hope.
It was a goal which Spain deserved, and it was little surprise that Iniesta was at the heart of it.
The Barcelona midfielder produced a typically majestic performance -- playing at a level which few opponents can cope with.
And yet, for so long, it appeared that the Czechs would escape with a hard-fought point after defending doggedly throughout.
Arsenal goalkeeper Cech repelled every effort which came his way, and when he was beaten the woodwork came to the rescue.
Roman Hubnik hit his own post while attempting to clear a cross, while Jordi Alba was denied as he looked set to score.
In the end it came down to Iniesta, who produced the perfect cross to the far post for Pique to head past Cech.
The Czechs rallied in an attempt to find an equalizer and Vladimir Darida unleashed a fierce effort which was brilliantly saved by David de Gea, who started the match after denying allegations Friday he had helped organize a sex party for two teammates in 2012.
The full-time whistle brought relief for Spain, which faces Turkey in its next match on Friday.
"The most important thing is the team's victory, not being MVP," man of the match Iniesta said after the game.
"We have a great team which can beat any opponent. Now we need to continue like this."
Croatia, which was hugely impressive in defeating Turkey on Sunday
, will face Czech Republic in Saint-Etienne.