And the Hibs boss added that doing it on the West Region giants’ own patch made the win “even sweeter”.
Gilbert saw his side secure a place in the fourth round of the Scottish Junior Cup last Saturday as they toppled Premiership outfit Rob Roy in a surprising 3-1 victory.
Goals from Garry Thomson and a single from Ben Anthony confirmed their place in the last-32.
And Gilbert reckons that this result could even top memorable wins over Arthurlie in 1998, and Petershill en route to their semi-final appearance in 2008.
He told the Gazette: “To win any tie in the Scottish Cup is great, but, when you go through to the west and win, it makes it even sweeter.
“There’s an expectation that the west teams are better. I think they have got that arrogance about them so the victory was the most pleasing thing.
“We’ve beaten Arthurlie and Petershill in the past but if this is not the best result in the club’s history, then it is certainly one of them.”
Thornton have reached the semi-finals of the competition just twice; once in the 1959-60 season and also in 2007-08 when they were defeated by Cumnock Juniors.
Gilbert refused to rule out another run to the latter stages but stressed it is all down to the luck of the draw.
He said: “The draw is going to determine how far we go. Ideally, the players would want an away tie as they see it as a bit of day out, but the management team want a home tie.
“Any team is capable of going on a run in the Scottish Cup. We’re now in the last 32 but we’re looking for a kind draw to continue in the competition.”
Thornton Hibs’ start to the season has surpassed expectations with Gilbert’s men flying high in third place in the revamped East Superleague. They have taken 18 points from a possible 27 which is far ahead of where they imagined they would be at the start of the campaign.
Gilbert said: “The performance against Rob Roy was great.
“We are playing well, we are confident, we are winning games and believe we can go to any team and turn them over.
“We are happy with the way things are going just now.
“Our expectation is just to stay in the league and avoid relegation so we are beyond where we thought we would be just now.”
The Hibs will be looking to continue their winning momentum when they face local rivals Kennoway Star Hearts in the League Cup on Saturday.
KSH have found the going difficult this season and sit bottom of the table after a 2-1 loss to Forfar West End.
Gilbert admits he has been surprised by their struggles.
He said: “It’s a first derby for the new manager Kevin Byers. I’m quite surprised where they are as they have got really good players. They had a bad result on Saturday but I am sure they will come good.”