Roberto Mancini expects his Manchester City side to face a stern test in their attempts to defend the Premier League title that they won last season.

Mancini's men ended a wait that stretched back to 1968 when they pipped rivals Manchester United to the trophy on goal difference with virtually the last kick of the campaign.

However, the Italian has warned his players that they can't afford to rest on their laurels as the new season draws closer.

"We did a good job for the last two years and I hope we can do a better one in the next five," he told the club's official website. "But we cannot rest or start thinking that because we won the title that we are the best.

"It is more difficult to win the title when you are defending champions. We start again as if from nothing; we must forget that we won the title. Every team will want to beat us and we must work harder than ever."

Mancini also revealed his belief that only United and Chelsea will be capable of wresting the title from his team's grasp.

"I think there are four or five teams that can challenge but now, before the transfer window is closed, I think United and Chelsea will challenge us for the title," he added.

Mancini took charge of the Citizens in 2009.