Pintado missed an even easier chance to double the score in the 57th minute when he scooped over from in front of goal but despite a spirited last few minutes from the visitors, the Swans deservedly held out for a crucial victory over their play-off rivals.
"I am pleased with the spirit and character my team has shown and I'm very proud of all my players," said Sousa.
"The team is growing in maturity and we want to get even stronger as the season progresses.
"Every member of the squad works for each other and I'm very happy because we are now in a good position in the division and we want to stay there."
But for indifferent finishing, Swansea could have been home and dry long before the final whistle.
The busy Pratley lashed a shot wide of the far post five minutes before the break but the most glaring miss came from Pintado when he completely miskicked when in front of goal following a run and cross by David Cotterill.
Foxes manager Nigel Pearson threw on Steve Howard and Martyn Waghorn up front on the hour as the visitors looked for an equaliser but the Swans held out for a deserved victory.
"I am disappointed but we didn't show enough quality and never passed the ball well enough to retain possession," said Pearson.
"We tried to put pressure on them higher up the field in the second half and it worked to a certain extent with our substitutions making an impact but we couldn't get the goal.
"We are still well-placed in the division and have to be reasonably pleased with our season to date.
"We have met Swansea three times already this season and after beating them in the two previous matches it is disappointing to come away with nothing to show for it."