City failed to sustain a title challenge last term and their record against the other teams that finished in the top seven proved a major shortfall.
In games against Chelsea, Tottenham, Liverpool, Arsenal, Manchester United and Everton, City - who ended the campaign third, 15 points off the top - collected just 11 points. They may have gone some way to addressing that by thrashing Liverpool 5-0 at the Etihad Stadium on Saturday.
De Bruyne, who set up goals for Sergio Aguero and Gabriel Jesus, said: "The only thing we didn't do last year was win the big games. I thought we deserved to win a few more games than we did, especially at home, like the ones against Tottenham and Chelsea.
"It makes a difference - that's five or six points extra and they are losing those points so then you are closer together."
City have spent more than £200million since the end of last season strengthening their squad for a renewed challenge.
De Bruyne said: "The guys who have come in have a very physical quality, they are very strong, very pacy. They make the pitch big, that is a quality of them and it is difficult for the other teams. To go around (Benjamin) Mendy and Kyle (Walker) you need to have a lot of trickery and pace and even then they can run back. That is the difference with last year."
The major talking point of Saturday's game was the sending-off of Liverpool's Sadio Mane after catching City goalkeeper Ederson with a high boot in a nasty first-half collision. Ederson left the field on a stretcher after eight minutes of treatment but was later cleared of serious injury.
City were already leading 1-0 at the time through Aguero's opener and went on to win comfortably with doubles from Jesus and Leroy Sane.
A number of City's players caught the eye but link-up play between strikers Aguero and Jesus was highly encouraging for boss Pep Guardiola. Aguero even passed up one good goalscoring opportunity to lay on Jesus' second of the afternoon.
Since Jesus arrived in January there has been much debate over whether the pair can play effectively together under a manager who has typically preferred to play with just one central attacker in the past.
Guardiola said: "It means a lot for me what Sergio did (passing to Jesus in front of goal). Both are good guys and exceptional players and both want to score goals, and we need that, but it is important they have the ability to choose the right decision like Sergio did when it was one against one with the goalkeeper. Next time Gabriel is going to do that to Sergio and that is good."
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