"After 15 games we are on the top, with two more points than United," he told reporters.
"The season is long. We have said that before. We are strong enough to start winning again and one result doesn't change anything."
City’s lead at the top of the table has been cut to two points after its 2-1 loss at Stamford Bridge and it could start the match against the Gunners in second place depending on Manchester United’s result against QPR.
Arsenal has won seven of its last eight Premier League games and will be confident coming into the match, but Mancini has backed his side to bounce back after their disappointment at Stamford Bridge.
"We don't have a problem bouncing back. I am sure we will," he explained. "At this moment, Arsenal are playing very well. It will be difficult but we need to start again."
Mancini is hopeful of having Micah Richards available after the full back missed the last fortnight with a calf injury.
"I think Micah will be OK for Sunday," said Mancini.
Pablo Zabaleta filled in at right-back against Chelsea, but with Gael Clichy suspended for Sunday’s match having been sent off against the Blues, the Argentine could be deployed on the left against the Gunners.
"We have Pablo, who can play on the left," he said.
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