Piggott, now 76, rode the first of the nine on Never Say Die in 1954 when he was 18, younger even than Joseph O'Brien who at 19 won the premier classic on Saturday with a devastating display on the brilliant Camelot for his trainer father Aidan.
It was an emotional day for the entire family with Joseph's mother Annemarie describing watching the race as "torture."
She then disclosed the role played by Piggott, the acknowledged master of Epsom's tricky turns and undulations.
"I met Lester Piggott last weekend and he said to tell Joseph not to be in any hurry and I knew when I saw him coming that he had timed it perfectly," she told reporters.
"I am really thrilled and it's incredible."
O'Brien jnr. was content to lay up at the back of the nine-strong field and only took closer order turning into the straight.
For a short time it looked as if he might have trouble hauling in front-running stable mate Astrology under Ryan Moore but caught him with 200 metres left and stretched away for an impressive five-length triumph to thrill the 130,000 crowd.
The victory puts Camelot firmly in line to emulate the great Nijinsky, the last horse to win the Triple Crown of the 2,000 Guineas, Derby and St Leger in 1970, all with Piggott on board.
O'Brien senior, who has had a host of top-class performers through his hands since his first licence in 1993, has always known Camelot had something special about him.
"From day one he's been exceptional so I was really taking it race by race," he told a media conference.
"He was very impressive in his two runs as a two-year-old and we were over the moon with his first run this year in the Guineas."
The Irish maestro added: "Every trip he's raced over so far he has been the same. He didn't look finished at the line today and it was the same in the Guineas. He relaxes."
Spare a thought at the other end of the race where 25-1 chance Cavaleiro came home last for Hayley Turner, only the second woman to ride in the race.
"He just wasn't good enough," observed Turner whose predecessor Alex Greaves also finished last on Portuguese Lil in 1996.