David Silva has warned his Manchester City team-mates that rivals Manchester United will never give up on the Premier League.
City briefly surrendered top spot at the weekend, but returned to the summit after a narrow 1-0 win over Arsenal on Sunday.
United are just two points behind after City lost at Chelsea last week, and Silva has warned they cannot afford to slip up again.
"We are aware that Manchester United are going to be pushing us all the way but we have to focus on ourselves," Silva said in The Sun. "You might say United have been disappointing but they are right there on our heels and you can't knock that.
"We know they are going to be right behind us so we have to make sure there are no slip-ups and try to win every game. We have to keep playing at the same level as we have been. To keep the gap as it is we have to keep winning our games."
City manager Roberto Mancini celebrated two years in charge at Eastlands this week, and Silva, who scored the winner for City on Sunday, believes that despite City's failure to reach the knockout stages of the Champions League, Mancini has surpassed expectations.
"I think Roberto is doing a great job. He got us into the Champions League for this season and the fact we are top speaks for itself," he said. "We also won the FA Cup last year and it would be nice to repeat that - but the Premier League title is the big target.
"We are playing some good football and let us hope the manager is repaid for this style with the title at the end of the season. I am really enjoying my football here."