Wrestling, an Olympic sport since the first Games in ancient Greece, looks set to be dropped for the 2020 edition, after the International Olympic Committee voted on Tuesday to remove it from the programme.
The decision, taken by the 15 members of the IOC executive board, has yet to be ratified by all members of the body but looks likely to be ditched, as seven other disciplines vye for inclusion in seven years' time.
An IOC source told AFP that the outcome was "a real shock", after modern pentathlon was expected to be the one sport removed from the list of 25 core sports for the Games to be held in either Tokyo, Istanbul or Madrid.
"Wrestling was not on the radar," the source said. "It was a very close vote between wrestling and modern pentathlon, maybe one or two votes separating them.
"The trouble was while modern pentathlon and taekwondo did effective lobbying, wrestling thought they were safe and did none at all."
Wrestling will remain on the programme for the 2016 Olympics in Rio de Janeiro but its likely disappearance will leave the Games with one of the few sports that survived from ancient times into the modern era.
It first appeared in 708 BC and has only ever not appeared at an Olympic Games in 1900.
Amateur wrestling's world governing body the International Federation of Associated Wrestling Styles (FILA) said it was stunned by the news, while one of the sport's powerhouses, Russia, said it would seek clarity on the ruling.
"FILA will take all necessary steps to convince the executive committee and members of the IOC of this aberration of a decision against one of the founding sports of the ancient and modern Olympic Games," it said on fila-official.com.
"FILA has always complied with IOC rules, is present in 180 countries where wrestling is a national sport for many, offering athletes their only chance of competing at the Olympics and contributing to the Games' universality."
Russian Wrestling Federation presdient Mikhail Mamiashvili said the threat of the sport not being at the 2020 Games was "real".
"I talked with (former Olympic pole vaulter) Sergei Bubka, who attended the meeting of the IOC executive board. We both were shocked by the recent events," he was quoted as saying by the Interfax news agency.
"Of course the IOC recommendation is a problem for FILA and its heads."
Wrestling is now fighting for a single place as an additional sport in 2020 against squash, roller sports, softball/baseball, karate, the martial art wushu, the water sport wakeboard and sport climbing.
A decision will be made on which sport makes the cut will be taken at an IOC meeting in St Petersburg in May, before both recommendations are put to all members of the IOC in Buenos Aires in September.
Squash and karate are generally seen to be leading the race.
In theory, wrestling still has a chance of being reinstated if non-executive committee members vote against the ruling but the recommendation is likely to be rubber-stamped.
Modern pentathlon's survival on Tuesday is a major coup for Juan Antonio Samaranch Junior, vice-president of the sport's governing body and a member of the IOC executive board, who is also a prominent member of Madrid's 2020 bid.
The discipline was widely seen to be at risk as it is expensive to compete in and does not attract a broad range of nations.
Invented by the founder of the modern Olympics, Baron Pierre de Coubertin, it first appeared at the 1912 Games and consists of five disciplines: fencing, horse riding, swimming, running and shooting.
The idea behind it stemmed from the skills required to be a 19th century cavalry officer.