The three-time Supercars champion shocked the racing world by winning the Chicago street race as a ring-in for Trackhouse Racing on Sunday – marking the first victory for a debutant in NASCAR's modern era.
While there was an expectation that van Gisbergen would be competitive given his vast street circuit experience in Australia, a victory on debut was still thought to be unlikely.
However, he charged to a fairytale win after running down Chase Elliott and Justin Haley before surviving overtime in fading light.
Leading van Gisbergen's victory was renowned crew chief Grubb, who has worked with the likes of Tony Stewart, Denny Hamlin and Carl Edwards.
When asked post-race to compare working with van Gisbergen to those greats, Grubb said: "I'd just say the professionalism and everything else, he's very similar to all those.
"I've been extremely fortunate in my career to be able to work with some of the names like you said, Jimmie Johnson, Casey Mears. All those guys had different qualities, and I think Shane has definitely got some of those qualities himself. He's just a leader.
"He came in very studious. He wanted to know. He was excited about Nashville. Like the commitment level he had, they left early from the Nashville race even though the #1 won. [He] didn't do the party because he knew we had to do the Roval test the next morning. He wanted to be back and be fresh for that.
"He asked all the right questions. If he didn't know what question to ask, he would say, basically, 'what am I not asking?' and we sat and talked a lot, and we ran through all the scenarios."
Grubb added that there were signs during a brief test at the Charlotte Roval last Monday that van Gisbergen could pull off an upset debut victory.
When asked at what point during the Chicago race he thought van Gisbergen may win, he said: "Honestly, for me, it was Monday when we did the test at the Roval.
"Watching his disciplined approach to managing tyre wear. We did 26 laps there at the end of the test just to let him feel how the tyres would fall off.
"We were running part of the Legends course on the backstretch, so it's nothing that even correlates to anything we do on the racetrack, but those are corners you felt like he could go attack and understand what it would be for a 90-degree corner somewhere.
"Those things, you see his talent level and you see him questioning his own ability, and he wanted to go in there and try it five different ways. You just sit there and watch. We don't have data on the car or anything, but you can see him learning with every lap.
"He could do consistent laps all day long, and then when he got to the simulator later in the week, watching how he had studied what the other guys had done and being able to go out there lap three and beat their lap times, in most cases, was pretty impressive.
"His feedback in the car matched exactly what we were expecting with simulation programmes and everything we do with Chevrolet. It was really awesome to see that feedback all match up."
For Trackhouse owner Justin Marks, the belief that van Gisbergen was capable of a miracle slowly increased in the lead-up to the race.
"I think for me, it kind of just built throughout the week," he said.
"We had a lot of hope and belief that he could be very, very competitive, but as soon as he landed, it was his focus and his understanding of what we were doing that was really, really impressive.
"He came to Nashville last weekend and sat in the box and was really plugged in asking questions, really absorbing it all. And then as the week went on, it was like one of the best sim sessions these guys have had, and great test, like Darian said.
He wanted to spend a lot more time on our static sim at the shop. He kept asking to go back to it and spent a lot of time on it. Then when we got [to Chicago], through practice, it just started building. We all kind of were like, 'man, we've got a real shot here'.
"But there's always that thing in your mind. It's like NASCAR races, they get kind of bananas. It's not just about the speed, right? It's about getting on and off pit road. He's never made this type of pit stop before, and these late restarts.
"There's just a lot of other variables. So that's always in the back of your mind, is that going to play into sort of how the race goes?
"But he showed so much speed in his approach and focus and everything in practice and qualifying, he just adapted to everything so well."
Marks said van Gisbergen's efforts during the lead-up to the race gave him confidence he could handle the late restart, despite having drivers hungry to make the play offs behind him.
"Typically the green-white-checkered is just like, oh, man, you're just nervous because it just goes crazy and things happen," he added.
"But the way they put the restart zone I was remarkably calm, honestly, for the restart because I knew if he just got through [turn] 12 and got the jump off there, that the whole build of the week... there was no anxiety about him making a mistake or missing his turn-in or anything like that.
"It was just, get to the white flag and get it done. He just put on a clinic. It was unbelievable."
