Not since Ruth a century ago has there been a baseball player capable of both pitching and hitting at the top level.
The 30-year-old's performances with the Los Angeles Dodgers have consolidated his position as a baseball legend in the making, and a national icon in his native Japan.
He continues to find new ways to amaze, this year becoming the first player to hit 50 home runs and steal 50 bases in a single season -- a feat previously thought impossible.
"He is amazing. Just amazing. I'm in awe," Tokyo shopkeeper Keisuke Takahashi told AFP in September after Ohtani's 6-for-6 batting performance against the Miami Marlins.
"He is too incredible... truly superhuman," added another Japanese fan on X.
Ohtani joined the Dodgers late last year on a 10-year deal worth $700 million -- the richest contract in American sports history.
His first year with the team has been even more eventful than anyone could have imagined, taking in marriage and a stunning theft scandal.
But it has been mostly defined by his consistent performances at the plate, putting him ever closer to the top echelons of American sport.
"You can compare him to the Jordans and the Tom Bradys of the world," said Deion Sanders, an NFL Hall of Famer who also played for nine seasons in MLB.
"That's who he is. He's doing things that we haven't fathomed."
Marriage and betrayal
Even by Ohtani's standards, 2024 has been an eventful year.
In February, he shocked the world when he announced that he had got married to Japanese basketball player Mamiko Tanaka.
Some of his former team-mates said they were unaware that the notoriously publicity-shy Ohtani even had a girlfriend.
A bigger bombshell was to come the following month when the Dodgers fired his long-time translator and close friend, Ippei Mizuhara.
Mizuhara later pleaded guilty to stealing nearly $17 million from Ohtani to pay off illegal gambling debts.
Mizuhara had access to Ohtani's bank accounts and would "plunder" it to commit "fraud on a massive scale", US Attorney Martin Estrada said.
It was the first setback of the squeaky-clean Ohtani's career, with the news breaking just hours after he had made his MLB debut for the Dodgers.
It failed to knock him off his stride on the field and seems to have done little to dim his eternally sunny disposition.
Ohtani has delighted in sharing the exploits of his dog Dekopin with fans, even bringing the brown and white pup onto the mound to "throw out" the first pitch before a game.
He has also fitted in seamlessly with his Dodgers team-mates, laughing and joking as if he had been there for years.
"I don't see how there is anybody more talented who has ever played the game than him," team-mate Kike Hernandez was quoted as saying.'One of one'
Born in northern Japan, Ohtani was a high-school star before joining the Hokkaido Nippon Ham Fighters in Nippon Professional Baseball.
He won a Japan Series title with the Fighters and joined the Los Angeles Angels at the end of 2017, but although he won rookie of the year honours, his early years in MLB were plagued by injury.
He never reached the postseason with the Angels but his individual success on and off the field in the US made him a hero in Japan.
"When you look at Ohtani, the image of the Japanese as physically smaller or inferior people just disappears," said Tokyo-based author Robert Whiting, who has written several books on Japanese baseball.
"He's set a new standard for Japanese, and everybody feels really good about it. He just makes people proud to be Japanese."
Ohtani has not pitched in his first year with the Dodgers but looks set to return to the mound next year.
Before then, he has the chance to win the one prize he values more than any other -- the World Series.
"He's one of one," said Dodgers manager Dave Roberts.
"He couldn't be a more talented player. He couldn't be more humble."
