The English 170-pounder is one of only three men to have fought both — Jake Shields and Frank Trigg are the other two shared GSP-Condit opponents — and he's the one who has done it most recently.
Hardy lost to both men. He survived five rounds with GSP at UFC 111 in April 2010, winning kudos for his grit, and was knocked out by Condit in the first round at UFC 120 in October 2010.
"The thing with Condit is he's just such a dangerous guy all the time. First round to the fifth round," said Hardy. "He's always got that ability to just steal the fight from you. To finish a fight, you've got to open yourself and take a risk. And Condit is the guy that steals it when you offer him that opportunity.
"I think GSP's an interesting matchup for him, because obviously GSP's game plan obviously doesn't allow people into the fight. He's very good at controlling the fight and keeping his opponent out. He did exactly the same to me — I did nothing offensive in the whole 25 minutes, I just couldn't.
"Condit is obviously in a better position to do that than I am. Obviously he's more talented off his back and things like that. I still think it's a very interesting matchup because we all know what GSP can do and we all know how Condit has to fight to win."
Hardy predicts a fourth-round GSP win, via rear-naked choke.
Hardy, who now fights out of Las Vegas, says he underestimated Condit's power when they met. A left hook changed all of that.
"He just doesn't look like he's dangerous," Hardy said. "I don't enjoy watching him fight, to be honest. He looks very awkward, he looks very cumbersome. He doesn't technically look very crisp. I never thought he did. And I was never very impressed with him.
"But I think that's what makes him dangerous, is that he is very unorthodox."
St-Pierre also beat Shields and Trigg, winning a five-round decision over Shields in his last fight (UFC 129, April 2011) and choking out Trigg (UFC 54, Aug. 2005).
Condit submitted Trigg and lost a decision to Shields the same night in Aug. 2006 on a Rumble on the Rock card in Hawaii.
Hardy has been helping St-Pierre prepare to deal with Condit's unpredictability. The Englishman and Canadian have become friends, in addition to sometimes training partners.
Hardy (25-10 with one no contest) doesn't expect to face GSP in the future.
"I think it's realistic to say our paths aren't going to cross again," said Hardy. "I think by the time I'm back up to title contention, he'll have moved on to much bigger and better and more lucrative things.
"It's a good situation right now. I can learn from him and help him out. I've got so much to learn from that guy — and the guys around him. He's got a great gym."
One of the Tristar Gym welterweights is Canadian Rory (Ares) MacDonald, seen as a future welterweight contender.
"He's impressive, I'm very impressed," said Hardy.
Training with GSP has allowed Hardy to see a different side to the champion. Hardy once thought he was somewhat robotic when it came to training and fighting, with little emotional investment.
"It's exactly the opposite," he said. "He's a very, very emotional guy. He over thinks things and he really analyses things. I mean that's why he's so good, because he really pulls things apart to the bare bones. He exposes people's weaknesses because he is so analytical.
"And he's just a very nice, laidback, well-spoken guy. I think he's a very deserving champion."
Hardy, who has won his last two fights after a four-bout losing streak that included the GSP and Condit defeats, expects to fight next in March or April.