England winger McGillvary earned plaudits after his two tries helped the Giants to Thursday’s 22-12 victory.
But caretaker coach Andy Kelly said Thorman was key in fashioning the game-plan that ended Hull’s 10-match winning sequence.
McGillvary agreed, saying: “I think he’s the brains. Andy’s really good with his words – he really gets the team up – while ‘Spug’ is more of a tactician.
“He’s been a head coach before in the lower leagues and was a good player, too, in a key position.
“He’s pretty clued up and does a lot of work with us defensively but I think all three of them –Spug, Andy and Luke Robinson – fit in well together; it’s helping us progress.”
The trio have been in charge since Paul Anderson was sacked last month – No 2 Kieron Purtill also left – and Giants have beaten Salford and Hull either side of a disappointing Challenge Cup exit to Wakefield Trinity.
Thorman, 35, captained Huddersfield in the 2006 Challenge Cup final but had a spell as player-coach of York following a disappointing 2009 campaign at Hull.
He is likely to take on more responsibility when Kelly heads to Australia in his role as England Academy coach after Friday’s game at Hull KR.
Penrith assistant Garth Brennan, North Queensland Cowboys assistant Dave Furner and Australian Brett Hodgson, the former Giants full-back on Widnes Vikings’ coaching staff, have been linked with the job.
McGillvary, who reached 150 career tries with his brace, added: “It was fantastic on Thursday, especially after the hard work the boys had been putting in the last couple of weeks.
“I know we didn’t win against Wakefield – that was embarrassing – but we’ve trained really hard since Paul left and dug in together especially defensively.
“To get a performance like we did, especially against a top side like Hull, was great.”
It saw Huddersfield pull clear of bottom place Leeds and, theoretically, they could still reach the top-eight with three games to go.
McGillvary, 28, added: “Even if we don’t win them all we need to be playing well for whichever eight we’re in. We have to finish off well and not be dragged into a relegation battle.”
Hull FC-bound Jake Connor, 21, created both McGillvary’s tries. “I said to Jake afterwards that’s the best complete game he’s played for us yet,” he said. “He’s only going to get better. He’s a great talent.
“I didn’t know about it being 15o until afterwards. It’s nice to reach milestones but I don’t think it’ll be until I’ve stopped playing that I really look back on them.”