Manchester, Dec 27 (IANS): It is impossible to replace Sergio Aguero, feels Manchester City manager Pep Guardiola. Aguero, 31, has 244 goals for the club which is a record and has a contract till 2021.

"He can stay but it depends on his physical condition and his desire," Guardiola was quoted as saying by BBC Sport. "Replacing him will be one of my biggest challenges because he is irreplaceable."

The City manager went on to laud Aguero for being so humble despite being a big soccer star.

"I've never seen such a big star be so humble and funny," Guardiola said. "He accepts my decisions when it sometimes doesn't work for him. Big stars don't (usually) do that.

"I've worked with other stars who believed they were bigger than Sergio when they weren't and they were more difficult to handle and to be with. It's not easy to find a guy with his status, his personality and what he's done in his career with his humility. He is a joy to work with."