The Portuguese grabbed a brace, whilst Riyad Mahrez, Phil Foden and Raheem Sterling all got their names on the scoresheet in a rampant display.
Pep Guardiola's men had six shots on target in the encounter and found the net five times, and it is that efficiency in front of goal that particularly pleased Bernardo.
"It’s a very good performance," he said. "In the first half we weren't that good to be winning 4-0. Sometimes we were sloppy and lost some easy balls, but we were very clinical.
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"You need some luck as well with very few shots on goal. I’m very happy with the win 5-0 away from home. It’s a good result and performance.
"Sometimes you play better than we played in the first half and you go in at 0-0 at half-time. We can still improve and be better."
The 27-year-old scored the second and fourth City goals of the evening, with his first a sumptuous volley which rattled in off the crossbar and his second a deflected strike.
Bernardo spent 12 years with Benfica, arch-rivals of Sporting CP and the midfielder admitted it felt extra special to score.
"I don’t know how I hit that ball that well," he admitted. "I’m happy to have helped the team. I’m happy with those two goals.
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"I’m Portuguese and from the other side of the city because I played 12 years at Benfica. It was special to score here in my hometown. It’s always an extra motivation to play in Lisbon."
Despite the 5-0 victory, Bernardo has urged City not to rest on our laurels and insists there is still work to be done in the reverse leg at the Etihad Stadium.
"It’s an important win, but there's still a job to do in Manchester, we can’t relax.
"Keep going, yes. In the Champions League you cannot relax. We tried to do our best no matter what the score was. It is a good score for us."