Roberto Mancini’s side scored twice in stoppage time to grab the needed three points and pip rivals Manchester United to the title.
City now celebrate their first title since 1968, and the Argentine believes the nature of the frantic finale will never be repeated.
Aguero told The Sun: "For sure it was the most important goal of my career.
"You score a goal in the last minute to win the title. I'm not sure that is ever going to happen again.
"QPR were fighting for their lives. They sat back and we knew they would make things difficult for us on the counter-attack."
Aguero hailed the City fans for making him welcome at the Etihad Stadium following his move from Atletico Madrid last summer and dedicated the title win to them.
The 23-year-old has vowed to bring more success to the supporters in the coming years at the club.
He added: "During the [pitch] invasion, loads of fans came over. They grabbed me and kissed me. But the only thing I understood was, 'I love you'. That made me so happy.
"Since I arrived at City, everyone has treated me really well. I repaid them with a goal to win the title and make history.
"I'll keep doing my best every day to win more titles. All I do is play football so the fans can enjoy themselves."