Belgium international De Bruyne opened the scoring at the Etihad Stadium as Pep Guardiola's men outclassed the Gunners to make it 31 points from a possible 33 in the Premier League this term.
The visitors were left disgruntled, though, when Oliver pointed to the spot for Nacho Monreal's challenge on Raheem Sterling. Sergio Aguero converted and, despite Alexandre Lacazette reducing the arrears, Gabriel Jesus' strike compounded their misery.
But De Bruyne defended the official's decision, claiming City could have had a penalty in the first half for a challenge on Sterling, and hailed a big three points for the leaders.
"We know Arsenal are a quality side but I think we contained them quite well. We created more chances and the third goal came at a good time," he said in quotes reported by BBC Sport.
"We should also have scored the second one in the first half. We kept our composure well and it is a great win for us.
"Obviously, it was great to score as it put us ahead and it's always nice every time you score.
"Maybe we got the benefit from the referee but the penalty was the second one of its type in the game. He had to give a penalty.
"The more you win, the more other teams want to beat you. It's been a great start for us so let's see what other games bring."