The Airlie Birds won 19-12 at Halliwell Jones Stadium after spending most of the second period defending their own line in a remarkable effort.
They had lost 80-12 on their previous visit there last August and were also beaten 63-12 at home to second-placed Warrington in March.
Asked if he had ever seen a better defensive effort, Radford said: “In terms of scramble, not really.
“We were just turning up for it. We got a gut full of their social media this week; it was outstanding how many points they’ve put on us previously but I just thought it was so disrespectful.
“It gets teams backs up that, I don’t like them (not) having some dignity.
“I don’t know what the word is but there’s a way to win and you don’t have to embarrass people.
“That certainly played a part. That was the team talk - job done.”
Radford also revealed how he lost three players to injury in their final training session yesterday.
“It was the team run from hell,” he said.
“Danny Houghton, Bureta (Fariamo) and Sika (Manu) all came out in one team run session so I was fearing the worst.
“But the glint they had in their eyes on Monday I felt showed with some of the efforts with our scramble defence for sure.
“The last time we played here I described it like we had a load of young kids going out.
“It was like Gladiator, where they p**s themselves before they go out into the Coliseum. That’s what the dressing room was like; they were sheepish and looking at the ground.
“I wanted to get up and cuddle them.
“Today there was a bounce in the changing rooms and a good energy and I felt they had a gut full of them of the stuff that has been said.”
Hull went behind Toby King’s early effort but then saw scored three converted tries in nine minutes from Mickey Paea, Scott Taylor and Albert Kelly to go in 18-6 ahead.
Blake Austin pulled one back at the start of the second half but - even after Jake Connor had been sin-binned for punching - FC did not buckle further and, instead, Marc Sneyd’s drop goal confirmed a famous victory.
Connor had earlier complained to referee James Child that Dec Patton had bitten him, an alleged incident that was put on report.
Full-back Jamie Shaul made a brilliant return to action, making three try-saving tackles after missing nearly two months due to concussion issues.
Scott Taylor was outstanding up front before going off in the 78th minute after a heavy collision trying to stop a rampaging Sitaleki Akauola.
He will be a doubt for the Magic Weekend clash with Huddersfield Giants.