Sergio Aguero must prove he deserves a new contract at Manchester City, manager Pep Guardiola warned.

Aguero returned following a four-month absence due to a knee injury as City recorded a 1-0 win at home to Arsenal in the Premier League on Saturday.

But the forward, who is City's all-time leading goalscorer, is out of contract at the end of the season and Guardiola said Aguero had a point to prove if he was to earn a new deal.

"Sergio now has to show, like every one of us, that he deserves to continue here – keep playing well, scoring goals and winning games – and after that the club and I will decide," Guardiola told reporters.

"But if he is playing in his level we don't have any doubts that he is a player to stay until he decides because he is unique. He is important for us, our fans and everyone.

"But he was out four months and he has to start training regularly and start to score goals – this is the most important thing."

Aguero has won four Premier League titles and numerous other domestic trophies since arriving at City from Atletico Madrid in 2011.

Guardiola is unsurprisingly happy to have the 32-year-old – who scored 16 goals in 24 league games last season – back from injury.

"Having Aguero on the pitch, we are better, we are safer," he said.

"We missed him a lot in the important moments at the end part of last season, but now is good news for us that he is back."

Since Aguero arrived at City in 2011, they have a better win percentage without him than with (70.7 to 67.4) in the Premier League, while on average scoring more often (2.4 to 2.3), as per Opta.

Those numbers are amplified since Guardiola took charge in 2016. Since then, City have won 78.6 per cent of Premier League games without Aguero and 71.9 with him, while scoring 2.7 goals per match when the Argentinian has been absent, compared to 2.4 with him.

City begin their Champions League campaign at home to Porto on Wednesday before making the trip to West Ham three days later.