Manuel Pellegrini has insisted that Raheem Sterling "has a big future" ahead of him at Manchester City.

The winger, who joined City from Liverpool in a deal worth a reported £49m last week, marked his debut during today's pre-season friendly against Roma with a goal inside three minutes.

Pellegrini was impressed with what he saw from the 20-year-old during his first-half performance, but he also stressed that Sterling will improve as he gets to know his teammates better.

"For a striker it's important to score, especially as he scored so early," the Chilean manager told reporters after his side had beaten their Italian counterparts on penalties.

"He just played 45 minutes as he's only worked a few days. He demonstrates why he's here, not only as player now but I think he will improve a lot in the future, playing with Yaya Toure, David Silva and Sergio Aguero.

"We bought him because he has a big future – he has the speed that we don't have so we have a different way of playing. He's the player we need in our team."

Sterling is next expected to feature for the Citizens against Real Madrid on Friday.