A historic 3-1 triumph over East Region high-flyers Camelon at the Clyde Gateway Stadium saw Glens reach the last four for the first time in 38 years – with Harvey watching from the terracing after being handed a six-week dugout suspension last week.
The Glens boss said: "I thought we won the game out of the park, but it is no real surprise to me because I know what my players can do when it all comes together for them.
"I have heard one or two remarks that Camelon never turned up on the day, but the reality is we got in their faces to make sure they couldn't play as they can, and to win 3-1 is our just reward for a lot of hard graft and commitment to a game plan.
"We knew they would look to start strongly and try to assert their passing game on us, so we deliberately set out to keep things tight early doors and bed ourselves into the game.
"Once their initial burst was quelled I felt my players got stronger and stronger, and a place in the semi-finals of the tournament is no more than we deserved.
"I don't imagine Shotts or the likes of Auchinleck or Linlithgow will be too worried about Glencairn right now, but neither are we concerned about who we get in the draw. Just to be in the last four is a fantastic achievement for a club like ours."
Although unfancied to overcome their visitors, it took less than 25 minutes for Stevie Aitchison & Co to make the transformation from underdogs to favourites.
Two goals in three minutes put them in control. Centre-back Brian Eadie volleyed a 22nd-minute opener, with Brett Agnew then touching home a searing Ross Ballantyne drive.
The home side suffered a blow approaching half-time when skipper Aitchison pulled up with a recurrence of the instep injury that had rendered him doubtful in the lead-up to the match, and he limped off to be replaced by another experienced campaigner Dean Muir at the heart of the Glens defence.
Any thoughts this enforced change might alter the pattern of play were soon removed as Glencairn continued to hold the upper hand on the restart with the combination of veteran Andy McLay's playmaking skills and the industry of Sean McGuire running the show in midfield.
Only a magnificent diving save by visiting goalkeeper Michael Watson prevented McGuire from a certain score in 71 minutes, however the engine room battler was not to be denied for long and, with 15 minutes left to play, he pounced on a half clearance to direct a 20-yard chip shot over Watson and high into the net for a 3-0 scoreline.
That strike sparked a mass exodus of visiting supporters who clearly felt sitting on their bus outside was preferable to watching their side being put to the sword.
Camelon did reduce the deficit when Colin Allison scrambled the ball home in a goalmouth melee, but it was merely a consolation.
Jubilant goalscorer Agnew said: "Camelon's reputation had us expecting a really tough time, but our attitude was spot-on and we blew them away in the first half.
"There are bigger fish to fry in the cup, but we'll appproach the semis in the same way and see where it gets us."
Also proudly taking their place as one of the Emirates last four standing are holders Shotts Bon Accord, who duly gave notice that whoever wants to prise the Holy Grail silverware away from their hands is going to have to play some.
Tony McInally's men were never behind in running out 5-3 winners down at Cumnock in a momentous end-to-end contest played in horrendous conditions.
Chris Walker's headed opener for Shotts was cancelled out by a John Bradford spot-kick, however Andy Scott and Stephen McGuire strikes saw the visitors go in at half-time holding a 3-1 advantage.
Bradford netting his second goal early in the second half acted to fire up the Ayrshiremen and it looked as if they might go on to cap an astonishing comeback when stopper Chris Robertson levelled at 3-3 with just 10 minutes left.
There was, indeed, a barnstorming finale, however it was to be all about Shotts as they went 4-3 ahead through Alan McKenzie and they duly secured a memorable triumph when McGuire netted from a spot-kick awarded when McKenzie was hauled down inside the area.
The remaining Emirates last-eight contests – Kelty Hearts v Auchinleck Talbot and Linlithgow Rose v Bo'ness United – fell victim to the wintry weather and will now go ahead this Saturday.