Liverpool take on City in the Carling Cup semi-finals tonight, and City will be without Kolo and Yaya Toure due to the Africa Cup of Nations and Vincent Kompany due to suspension.
"Toure and Kompany are their key players but they will still be strong," Skrtel said.
"But we can beat them. We made three mistakes and conceded three last week."
Manchester City defeated Liverpool 3-0 when the clubs met in the Premier League last week.