The Tykes eventually progressed 5-4 courtesy of Chris O'Grady's decisive kick,
following a goalless 120 minutes of play in the first-round tie at Oakwell.
"It's something we need to work on," Flitcroft said. "We're a club moving and
there's been plenty of mad results tonight.
"We've got a plan and we'll keep improving. We do know that. We've got to keep
"But overall the ball management was good and the energy levels were very
"A lot of those lads played 90 minutes against Wigan on Saturday and they've
done 120 tonight.
"Chris O'Grady was running on empty but he still had enough left in the legs
to stick that one away at the end and I'm delighted that he pulled us through."
Scunthorpe boss Brian Laws hailed his side's battling performance.
Laws said: "I'm really disappointed for them because they put so much effort into it. Over two hours of football and we kept a clean sheet against a Championship side away from home.
"That's two games now where we've gone away with a clean sheet. We craved for
them last year. I think there's a steeliness about us now and a great desire.
"The only downside of it is that it had to be decided on penalties. I don't think either manager really wants to see that because it can affect your next game - it's the last thing you want so early in the season."