The former Manchester United maestro scored Real's winner in the 2-1 victory at the Nou Camp - silencing those who believe he does not perform well in big matches.
Real Madrid have all but secured this year's La Liga title as the victory put them seven points clear of their fierce rivals with only four matches remaining.
Ronaldo's 73rd-minute winner took his season's league goal tally to 42, one more than Barca's Lionel Messi, who finished the game without a goal.
If Real do win this year's title, it would be the first time they have done so in four years, when Fabio Capello won the league in his one and only season at the Bernabeu.
Regardless of how this season pans out, Ronaldo has had another year to saviour and has now scored 54 goals in all competitions this season.
Speaking after the match on Saturday, he said: 'It was a very important goal because it earned the three points for us.
'I have scored the last three games I played here, but the key to the match was the team,' added the 27-year-old, who became the world's most expensive player when he joined Real from Manchester United three years ago.
'The seven-point lead leaves us in a comfortable position, but we have to remember that the next games are also key.
'The team is in good shape, on form, happy, filled with desire and aware of its responsibilities.'
Buoyed by Saturday's victory, Real Madrid take to the Bernabeu pitch on Wednesday to face Bayern Munich in the second leg of the Champions League semi-final.
Real trail the Bavarian giants 2-1 after a tense encounter in Germany last week, but their away goal could prove crucial.
Barcelona are also seeking to make it to the final of the Champions League when they host Chelsea at the Nou Camp on Tuesday. Chelsea won the first leg at Stamford bridge courtesy of a Didier Drogba goal just before half time.
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