Grey was a solidifying figure in an Australian side that suffered a comprehensive defeat in the first rubber but bounced back to take the series 2-1 in one of the most memorable Lions' adventures ever.
The former Waratahs star won a World Cup winners medal with the Wallabies in 1999 and experienced Tri Nations success against the All Blacks and Springboks but he admits beating the Lions was something very special.
"It was magic. Playing those Tests against the Lions was definitely one of the highlights of my career," said Grey.
"It's the ultimate challenge. When you get given that opportunity to face the Lions you've got to make sure you're ready and totally switched on because you're playing against a side that's got a lot of history and is full of bloody good players - that's a big, big challenge.
"One of my highlights from that tour was when I was playing for Australia A and we beat them up in Gosford. That was very much unexpected on all fronts.
"With the Wallabies, we were expecting ourselves to beat the Lions and that first Test in Brisbane was unbelievable. I remember running out and just seeing a sea of red. That was magic.
"I'd played all over the world but that Test was something else. I remember running out thinking, 'Holy shit, this is awesome, but they're in the wrong colours!' That gave the Australian Rugby public an example of how you support your team.
"We got beaten in the first Test and then we had the second Test in Melbourne. The Australian Rugby Union obviously realised that they had to get some gold out there in the stands so that was brilliant for our game, too."
Nathan Grey (pictured) and co struggled to get to grips with Brian O'Driscoll in the first Test in 2001
That first Test at The Gabba always ranks highly in Lions' memories but it was the nature of what followed that will live even longer in the hearts of Australian players and supporters alike.
Having been on the wrong end of a hammering in Brisbane, the world champs looked well on their way to losing the series a week later in Melbourne as they found themselves under the cosh and behind on the scoreboard at half-time in the Colonial Stadium.
But then the Wallabies did what they do best - they showed their mental resilience to somehow snatch victory from the jaws of defeat.
A Joe Roff try from a Jonny Wilkinson intercept moments after the interval turned things in their favour and the Wallabies never looked back.
And while the rest of the world had been writing them off following the comprehensive nature of their first-Test dismantling, Grey insists there was never a flicker of doubt that he and his team-mates wouldn't get the job done.
"In my time with the Wallabies - and I'm sure it's the same now - you expected to win every Test you played in," added Grey, who won 35 caps between 1998 and 2003.
"You realised that if you trusted your processes, trusted the guys around you and executed your game plan, you were going to win.
"Saying that and doing that are two different beasts but I think the Australia side we had back then was pretty strong in terms of determination and wanting to get the job done. And what better environment to test yourselves in than against the Lions - against the best.
"In the first half in Melbourne we were under the pump but we got our act together and got away with a win in that second Test. Then the win in Sydney was amazing. It was a special time in my life and my career."