The Latics have yet to find the net away from home since the opening day of the season and suffered more frustration in a goalless draw with Charlton.
Chris McCann came closest with a second-half header which hit the crossbar while Grant Holt, James McCarthy and Ben Watson also missed decent opportunities late on.
"You saw the chances but we need to be more ruthless," admitted Latics boss Coyle.
"Credit to Charlton, but over the piece and with the clear opportunities we had we should be leaving with the three points.
"But I'm not unduly worried. We've got good players. We've got to keep banging on the door and then there will be a flood.
"A few things were said at half-time because in the first half we were below standard, and in the second half we were terrific.
"You can't fault the players' energy, desire and what they're bringing over the season. We will be where we need to be."
Wigan, still getting to grips with combining their Thursday night Europa League outings with a promotion bid, looked lethargic in the first half.
They were indebted to rookie goalkeeper Lee Nicholls, who was thrust into a league debut after Scott Carson was injured in the warm-up, for keeping the scoreline goalless at half-time.
The 21-year-old twice denied Bradley Pritchard in the opening stages and then pulled off a stunning save to keep out Richard Wood's point-blank header.
"Scott turned his ankle in the warm-up," added Coyle.
"There was a game abandoned on this pitch earlier this season because of the rain and maybe it's a bit soft underneath.
"We have tremendous faith in Lee but it's a big ask to replace Scott Carson.
"He took his crosses very comfortably and had one terrific save to make from the header in the first half.
"It speaks volumes for the kid that he had 25 minutes to get ready for a tough Championship game and acquitted himself in great fashion."
Charlton's best opportunity fell to Pritchard, who latched onto Cameron Stewart's cut-back 14 yards out but skied it over the crossbar.
Manager Chris Powell, whose side are now unbeaten in four matches, said: "We certainly had the better of the first half and Bradley had a gilt-edged chance. But I think the result was fair.
"We knew they would come into it in the second half and they had chances and hit the bar.
"But I have to remain positive, it's another clean sheet after the troubles we had earlier in the season and it's good for our confidence."