Kenny Jackett admits his Wolves side lacked a cutting edge in their JPT loss to Notts County and never got going until the second half.
County dominated the second-round tie at Molineux and victory was no more than they deserved, with Wanderers indebted to goalkeeper Carl Ikeme for even taking the game to penalties.
County won the shoot-out as Wolves trio Bjorn Sigurdarson, Kevin Foley and James Henry all missed from the spot, coming with the clash having finished goalless after 90 minutes.
"We finally got going in the second half and built up a head of steam but didn't do enough," Jackett said.
"Leigh Griffiths was lively but we didn't really give him the service or the quality that he needed.
"Having said that we didn't do well enough in the first half to get going. We didn't move the ball quickly enough. It took us a long while to get going but we pretty much had all the play in the second half but didn't do enough with the ball.
"Around the box we didn't have enough inventiveness, have enough shots or go past people enough to affect the game and create the chances we needed. We want to be scoring goals and threatening the opposition box.
"From my point of view I have to learn from it very quickly because when we do start again we have an absolutely vital run of games in the league.
"We are disappointed to lose but putting the knowledge gained to good use is a vital component. The assessments to be made will be important going forward."