Steven Pressley hailed his hero goalkeeper Chris Maxwell after a double penalty save saw Fleetwood through in the Johnstone's Paint Trophy.
Maxwell denied Billy Sharp and Jay McEverley as Town took control of the penalty shootout - the tie with Sheffield United finishing 0-0 after 90 minutes.
Bobby Grant, David Ball, Jimmy Ryan and Nick Haughton were on target from the spot to secure Town's spot in the Northern Area semi-final - Jose Baxter the only Blades man to find the net.
"It's two brilliant saves, the first especially," said Pressley.
"To just get to that, never mind having the strength to keep it out.
"It was an excellent save from him.
"He's been fantastic since I came to the club.
"It's pleasing to get another clean sheet for him."
Fleetwood bossed much of the game but were unable to turn chances into goals.
Sub Ash Hunter went closest to breaking the deadlock - his spectacular 25 yard effort tipped onto the underside of the bar by George Long.
There were chances too for Declan McManus, who profited from the wide threat created by Tyler Forbes and Amari'i Bell.
Progress in the competition will certainly lift spirits at Highbury.
With Town still struggling in the bottom four of League One a cup run could be the confidence boost Fleetwood need.
But Pressley again made it clear he wants to see more from his side in front of goal.
"We're really pleased," said the Fleetwood boss.
"I've said we have to be better in the final third.
"That was evident again.
"But our organisation, our willingness to do the dirty side of the game was good.
"At times we passed the ball very well.
"But the final ball, the final pass, we just lacked a bit of confidence around the box.
"That will change, things will get better.
"The most important thing is that we're winning games of football.
"There's a really good feeling in the dressing room after this one.
"There's a good spirit about us.
"I'm delighted because this is a competition I'd love to see us progress in.
"This is a competition which gives clubs like ourselves a real opportunity to play at Wembley.
"We're three games away from that and that's an exciting prospect."
Town created more chances than they have in any of their recent outings.
But a lack of confidence around the opposition box was clear and a source of frustration for Pressley.
"We're definitely getting a little more intensity to our game," said the Town boss.
"I said when I came in the starting point was clean sheets.
"But now I want to be a team that creates and scores more.
"It's the final moment, the final decision.
"We had a moment tonight where Amari'i Bell broke through, he had the chance to play in to Jamille and it was just sloppy in the end.
"Those are the things we need to tidy up."
Nick Haughton hammered the final nail into the Blades' coffin and Pressley was encouraged by his calm under pressure.
"Nick great, he's a special player," said Pressley.
"I'm really excited about Nick, he's a player slowly, in time, we'll see the best of.
"He's getting fitter and stronger all the time.
"He showed the character and the cool under pressure to score that vital penalty."
Town made four chances, Conor McLaughlin absent on international duty, Jamie Proctor and Antoni Sarcevic rested ahead of Saturday's trip to Peterborough - Jamille Matt and Declan McManus given the chance to prove themselves.
Fleetwood will know their JPT opponents before they kick off at London Road - the draw taking place on Saturday morning.
Wigan, Barnsley and Morecambe will join them in the pot.
"We'll take anybody at home." joked Pressley.