Lawn, who admits he is "probably the only chairman with a tattoo of the club on his arm", woke up with a thick head on Wednesday morning "after a few sherberts" and the dawning realisation that League Two side Bradford are only two semi-final legs away from a dream final.
It is a far cry from the grim years of 2002 and 2004 when the club suffered two administrations, and two relegations, following a period of over-spending in the Premier League.
Lawn, who bailed out the debt-laden club in 2007, admits he was expecting the worst when he saw Arsenal boss Arsene Wenger had put out a full-strength team.
He said: "When I saw the side they put out I thought we were going to get hammered but the lads did brilliant.
"We were a fourth division club up against a Champions League team - because that's what Arsenal were last night - and what our lads did was quite amazing.
"I have been a Bradford fan all my life - I'm probably the only chairman with a tattoo of the club on my arm.
"I went to my first match in 1964 when I was four, and last night ranks up there with the greatest in our history. Given the gulf between the sides it has to be up there.
"We've only one player who cost a fee, and that was James Hanson for £7,500.
"Phil Parkinson got his tactics absolutely perfect. We have to give a big shout out to all the management team, in fact to everybody, right down to the cleaning lady. "
Lawn, the founder of a nationwide driver recruitment business, celebrated last night in the way he knew best - with the friends with whom he used to stand on the terraces at Valley Parade.
He added: "I didn't get to bed until past 5am. I had a few sherberts with some of the lads I used to go to matches with, and sung a few of the old songs."
The victory has changed Lawn's attitude to the opponents he would like Bradford to face in the semis. Instead of another glory tie with Chelsea, the prospect of progressing to the final has made Lawn question whether the Bantams would be better off facing Championship opposition.
"I did say Chelsea originally but now I'm thinking maybe Leeds or Boro to have more of a chance getting to Wembley," he said.
"Leeds would certainly be a money-spinner but there would be a lot of stuff off the pitch to contend with too.
"The most important thing is that we are in the semi-final.
"This club has been through such a lot, a £34million administration the first time and then a second administration and I got involved after that to get us onto an even keel.
"A lot of praise has to go to [co-chairman] Julian Rhodes whose family nearly lost everything including their houses supporting this club.
"It was a great, great night for this club against Arsenal, and one that nobody who was there will ever forget."