A glut of second-half goals ensured a vital victory for City, which moves them two points clear of Liverpool at the top of the table with just Sunday's home clash against West Ham to come.
Pellegrini's men had been frustrated by a well-organised Villa side in the first half, but Edin Dzeko made the breakthrough in the 64th minute before adding a second eight minutes later.
Substitute Stevan Jovetic then all but confirmed victory in the 89th minute, before Yaya Toure applied the finishing touches to a determined display with a fine individual goal in injury time.
And Pellegrini was quick to hail a performance that ensures City will need just a point against West Ham to win the title, barring a huge swing in goal difference.
"The team was not only very patient, we played very well," Pellegrini told BBC Sport.
"We pressed well, had possession of the ball. We tried to move the ball as fast as we can and created two or three chances.
"I was absolutely sure if we continued to play the same way we would find the space to score a goal.
"Now we can talk about the title. We must win the last game against West Ham."
