Francis-Henri Graffard's colt struck Classic gold on what was his seasonal debut in the Poule d'Essai des Poulains in early May, but his summer campaign has been interrupted, with a planned visit to Royal Ascot scuppered by a minor setback after which he ran a little below par when fifth in the Prix Jean Prat.
He had plenty on his plate stepping back up to a mile, with Aidan O'Brien's Irish 1,000 Guineas and Coronation Stakes winner Precise the hot favourite after bumping into top-class older filly Blue Bolt on her last couple of starts.
Fozzy Stack's Prix Jean Prat victor Thesecretadversary took the field along for much of the way, closely pursued by Karl Burke's Zeus Olympios, who looked the likely winner after quickening to the lead inside the final furlong.
But Mickael Barzalona delivered Rayif with a withering late run and he got up to deny Zeus Olympios an elusive first Group One success, with Precise close up behind in third.
"I'm very happy, it's a wonderful race to win, a very hard race to win," said Graffard.
"I kept my confidence in the horse. He ran pretty well the other day with excuses and he was in top form (today). Over that course you need the perfect trip and we had the perfect trip today.
"He travelled really well and picked up really nicely, he's very tough and game.
"He won the Poule d'Essai on very soft ground so everyone was saying he's a soft ground horse, but you need to keep trying and if these horses are to find their place at stud they need to be performing at this level.
"The Jacques le Marois is a very famous race - probably the second most famous race in France after the Arc - so it's a wonderful race to win. It means so much."
Rayif has a range of options for the second half of the season, including the Queen Elizabeth II Stakes at Ascot on Champions Day, for which he was cut to 4-1 second-favourite from 14-1 by Coral.
Graffard added: "It depends if we decide to go for the Prix du Moulin (September 6) or give him more time and the Prix de la Foret (October 4) could be an option - I wouldn't be afraid to drop him back in distance.
"There is the QEII at the back-end and we know he can handle soft ground."
Of the gallant runner-up, Burke said: "We always thought and hoped he would produce that sort of performance in a Group One. I think physically he's improving and he showed that today.
"He quickened twice there - first time I thought we'd got it, then he got challenged and then he quickened again and I thought we'd got it and so did Cliff (Lee, jockey).
"The winner, fair play to him, has come and cut us down. Francis can do no wrong, can he?
"We'll get him home and see how he is. It's got to be discussed, but as a trainer I'm very hopeful he'll stay in training next year and I think he'll just continue improving physically and strengthening, so hopefully if he doesn't win his Group One this year he'll certainly get it next year.
"I'd say the race at Longchamp (Moulin) will probably come a bit quick for him, maybe we'll wait for the QEII at Ascot."
