After clawing their way out of the bottom three last week, Wigan are back in trouble following a 3-2 home defeat by Sunderland.
"We never take anything for granted," he said.
"If we had done that we would never have had eight seasons at this level.
"Today we weren't good enough defensively for 30 minutes. We need to rectify that.
"Ivan Ramis' injury last week cost us today's points. That is something I need to correct."