Manchester City manager Manuel Pellegrini heralded Stevan Jovetic's perseverance after the Montenegrin striker scored twice in the Premier League champions' 3-1 win at home to Liverpool.

Jovetic, 24, endured a frustrating debut campaign at City, with injury and illness restricting him to only 11 league appearances, but he appears rejuvenated after a successful pre-season.

He scored either side of half-time in Monday's game at the Etihad Stadium -- taking him to within one goal of his tally for the entire 2013-14 campaign -- and Pellegrini said it was a reward for his determination.

"He was very unlucky last season, but we never had any doubt about his quality," Pellegrini told reporters.

"I'm very happy for him, because after such an unlucky season, he deserves to start this season the way he's playing.

"Not only for his goals. Stevan was working the whole game, without the ball also."

Jovetic told Sky Sports: "There are so many beautiful moments now, after so many problems last year, but I don't want to think about that as it's the past.

"I just want to enjoy (playing) with this team, with these players, and to win as many titles as we can."

With Alvaro Negredo sidelined by injury and Sergio Aguero working his way back to full fitness after his exertions with Argentina at the World Cup, Jovetic has acquired extra importance for the defending champions.

But Aguero also made an impact against Liverpool, scoring just 23 seconds after coming on for Edin Dzeko in the second half.

Pellegrini said that Dzeko would undergo tests on Tuesday after the Bosnian striker took a kick to the leg, but the City manager described it as "nothing important".

Jovetic's display took the spotlight away from Mario Balotelli, the former City striker, who watched the game from the director's box after completing his £16 million ($26.5 million, 20.1 million euros) move to Liverpool from AC Milan.

The Italy international arrives with a reputation for causing trouble, but Liverpool manager Brendan Rodgers described his transfer as "a calculated risk".

"I think that in the market to get someone in at that quality, the deal for us was very good," said Rodgers, who saw another new signing, Rickie Lambert, force Pablo Zabaleta into scoring an 83rd-minute own goal.

"He is a world-class talent and it is an area we need to strengthen. It is a calculated risk, but one where we believe can help him as a player and to mature as a young man.

"I don't have any concerns at all, to be honest. He comes in with a reputation, but we hope at our club we can curb that behaviour.

"He knows he is part of a team. There are no egos and 'big time Charlies' in our squad. This is a group that's got to the Champions League because they are a team."

Rodgers added: "I think there's excitement with them (about Balotelli) coming in. I'm certainly looking forward to it.

"One thing he doesn't lack is confidence. He has that belief and football arrogance, and the best teams have that."

Monday's game saw Rodgers hand competitive debuts to Alberto Moreno, Lazar Markovic and Emre Can, while Lambert and Dejan Lovren were playing in only their second games since joining from Southampton.

Balotelli's arrival means that nine players have joined Liverpool during the close season -- with Divock Origi having been loaned back to Lille -- and Rodgers warned that it will take time for them to bed in.

"If you buy players, it doesn't guarantee you anything," he said.

"You can spend as much money as you want, but it doesn't guarantee you anything. I'm only confident that they are going to get better."