A man required CPR in the stands and was stabilised after 20 minutes, before an ambulance came to the stadium to take him to a nearby hospital.
Play was stopped just ten minutes in after Hornets left-back Adam Masina went down with an injury, but the match did not resume as it became clear a medical emergency was unfolding in the stands.
Protocol meant the players were taken off the field by referee David Coote, while Amazon Prime reported that paramedics and Chelsea’s medical staff were giving CPR to a man in the crowd.
After a 15-minute pause, it emerged the players would not come out before they had definitive news on the status of the fan. Shortly afterwards it was revealed that the supporter had been stabilised and would be taken to hospital.
Watford and Chelsea players are back on the field. Both sets of players have a short warm-up before the match resumes Clapping hands sign
The score is currently at 0-0, with the hosts making a very strong start and going close through Joao Pedro and a cross that deflected off Cesar Azpilicueta.
Final Score is 1-2