Tentoglou is no stranger to such things, having won Olympic gold with his final jump in Tokyo after being out of the medals after five rounds.
It went the other way in Eugene last year when he was leading after five only for Wang Jianan of China to come from nowhere, take gold and demote the Greek to silver.
Tentoglou got Thursday's final off to a flier as he produced a huge season’s best 8.50m with his opening jump, only for Pinnock to match it in the second round.
That put Pinnock, who flew to a world-leading 8.54 metres on his opening jump in Wednesday's qualifying and a personal best by 17cm, in the lead on the back of having the best second jump by one centimetre.
In the final round, though, Tentoglou hit the board perfectly to soar ahead and Pinnock was unable to improve on his final attempt.
"When he pulled that off I couldn't believe it but then I could, of course, I know what he's capable of," said Pinnock.
"I just knew he had it but I just didn't know he would do it, that he would pull it off at that moment.
"But this is still a silver medal. It's really a dream come true. Watching people like Tentoglou gave me the motivation as a youngster to reach the top. And now I'm there, nearly there."
Jamaican Tajay Gayle (27) snatched bronze with his final leap of 8.27m, matching compatriot Carey McLeod (25) but edging him on countback.
McLeod was lucky to escape injury after slipping on takeoff on his third jump, spiralling spectacularly into the air and landing face-first into the pit.
