McCarthy believes only a more ruthless streak in front of goal is standing between Wigan Athletic and Premier League points.
"We're obviously very frustrated at the moment," he told the Wigan Evening Post .
"I thought we passed Sunderland off the pitch, even when we went down to 10 men, and we just couldn't take our chances.
"Their goalkeeper made a few great saves but when you get into those positions you have to be taking some.
"I thought we deserved all three points for that display, but it wasn't to be.
"We can't afford to get too downbeat. We've got a massive game against Everton next week, which we need to be up for both on and off the field."