"He's amazing, a player with qualities that it's difficult to find in any other player," said Villa.
"He's fast, he's really good in one-on-ones, and this year he's scoring a lot of goals. He's improving year by year, which is the most important thing for a soccer player.
"When you're 18, 19, 20, and playing at the highest level, for teams like Liverpool and City, the most important thing is to get better every year.
"It's important to grow as a player and every year Sterling has done it. You see he's a better player day by day, year by year, and he's still very young."