With criticism at home mounting and hopes of ending a 44-year World Cup drought fading, England finally played with the determination that had been missing in two timid draws against the U.S. and Algeria in Group C.
"That result can breed confidence for everyone and keep us going," midfielder Gareth Barry told reporters.
"I thought we approached the game well, especially in the first half with the amount of pressure we took into the game. We played some good football.
"Now that we are into the knockout stage anything can happen. We've got to believe in ourselves."
A win over Slovenia would not normally be considered a springboard to a trip to the World Cup final, but the European minnows had been the surprise package of tournament sitting atop the group standings heading into the final matches.
Striker Jermain Defoe rescued England's stuttering campaign with a first-half strike as the Three Lions went on to dominate match in a confidence-boosting victory.
"This is a relief. It's a good start," said Joe Cole. "Now we can push on and try to win this World Cup.
"If we play the way we played today, anything can happen."
Now that a spark has been lit, coach Fabio Capello is confident that England's competitive spirit will continue to burn bright through the remainder of the World Cup.
"I saw the team play with the spirit that we lost in games before this," said Capello. "The performance of the team was very good and we had a lot of chances to score the second goal but we didn't.
"This is the spirit that I remember in the qualification games. We played hard. Every moment we met the ball, we made the tackle.
"I'm sure we will play with more confidence because we rediscovered the spirit."
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