Kilmarnock's Scottish Premier League game against Hibernian at Rugby Park was abandoned in the second half after a fan was taken ill.
A male supporter was taken to hospital in an ambulance after receiving medical treatment for a suspected heart attack at the side of the pitch in front of the East Stand.
Referee Kevin Clancy had initially stopped the game, which was tied at 1-1, five minutes after the interval, but the players left the field when the seriousness of the situation became clear.
The club subsequently confirmed the game had been abandoned due to an off-pitch incident.
Inspector Sean Mangan, the match commander, told Sky Sports: "A 50 to 60-year-old male was taken ill in the East Stand - possibly a Kilmarnock fan.
"Ambulances and medical staff have been assisting with that male; he's now gone off to the hospital in the ambulance. It's looking like a possible suspected heart attack.
"It's certainly serious enough that the club, in conjunction with the police and the SPL fourth official, has decided out of respect for the male, and possibly his family, that the match would be abandoned.
"It was abandoned out of a moral factor and out of respect for this man."
Kilmarnock manager Kenny Shiels revealed he and Hibernian counterpart Pat Fenlon both concurred with the decision.
"Obviously it was quite serious so Pat Fenlon and I both agreed that the game
should be abandoned," he said.
"We need to show respect to the relevant families. "Football is not as important as human life so we have shown our respect.
"There is no decision (about the replayed game), we are thinking Wednesday week, the 15th of May, that is not a definite but the most likely date."
In March 2012, Killie's League Cup winning celebrations following their victory over Celtic at Hampden were cut short following the death of midfielder Liam Kelly's father from a heart attack.
After paramedics worked to revive him at the final whistle, Jack Kelly was rushed to hospital but died within hours.
A month later an Inverness fan collapsed and died in the Frank Beattie Stand midway through the second half of a game against Killie.