The Tykes eventually progressed 5-4 after Chris O'Grady's decisive kick, following a goalless 120 minutes of play.
But the Iron often looked the better side against their lacklustre opponents and Laws admits it was difficult to find any negatives in his side's display.
"My thoughts are that they were magnificent," he said. "You need commitment to put in a performance and it was there in abundance.
"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."
He added: "But the players said if we're going to go this far then we're going to try and win this game. If it takes over two hours then that's what it takes.
"The players will pick themselves up. We'll pick them up obviously and we'll look after them over the next couple of days."
- Sports & Recreation