Costa Rica hero Ruiz revels in win
Ruiz met Junior Diaz's perfectly placed left-wing cross with a powerful header that crashed off the underside of the crossbar and over the line to give Costa Rica the lead in the 44th minute at the Arena Pernambuco in Recife.
A below-par Italy were unable to find an equaliser in the second half as Costa Rica held on to progress beyond the group stages at a World Cup for only the second time and dump England - who lost their opening two games - out of the tournament.
And Ruiz was quick to hail Costa Rica's achievement in beating both Uruguay and Italy, a feat that few would have thought possible before the start of the Brazil showpiece.
"I cannot explain the emotions I am feeling right now," Ruiz told Sky Sport Italia.
"We suffered so much in this game. I dedicate the goal to my family and it's incredible to score at a World Cup.
"We had dreamed of this moment, even though we knew people didn't believe in us.
"We qualified ahead of teams much stronger than we are, so this is all a dream come true.
"We thank all those who did believe in us, as we've achieved something extraordinary considering our country is so small."