Sergio Aguero
Manchester City's Sergio Aguero celebrates after scoring during their English Premier League match against Swansea City at the Etihad stadium in Manchester. REUTERS

Sergio Aguero struck twice on his debut after coming off the bench as Manchester City beat Premier League new-boys Swansea 4-0 on Monday night.

Aguero, who joined City in July for a club-record £38m, entered proceedings in the 60th minute after Edin Dzeko had opened the scoring for the hosts; netting the rebound after Swans goalkeeper Michel Vorm parried an Adam Johnson shot at his feet.

Eight minutes later the Argentina international put a rampant City 2-0 up when he converted Micah Richards' low cross into an empty net.

The second-half substitute then turned provider when he hooked the ball back into the path of Silva to volley home, with Vorm beaten.

But Aguero saved the best for last, thundering a brutal, dipping shot away from Vorm's outstretched dive from 30 yards, as Roberto Mancini's side opened their title campaign in emphatic fashion.

"He needs two or three weeks to be 100 per cent," Mancini told Sky Sports.

"For me he is a fantastic striker, he is young. I'm delighted after this performance but I think in the first half Swansea played very well."

Swansea held their own in a tight opening period but rarely troubled Hart as they faded badly after the break.

"I said to the players I was very, very proud of them tonight," manager Brendan Rogers said afterwards.