Premier League footballer Fabrice Muamba is in intensive care after collapsing during an FA Cup tie.
The 23-year-old was said to be critically ill in the London Chest Hospital after falling to the ground at White Hart Lane in front of millions of television viewers watching the sixth round tie between Tottenham Hotspur and his club, Bolton Wanderers.
Outside the hospital, the club's manager Owen Coyle said the following 24 hours were "absolutely crucial" and urged people to pray for the player's recovery.
Members of Muamba's family and his fiancee attended the London Chest Hospital on Saturday night, the BBC reported.
A Bolton spokesman said: "Bolton Wanderers can confirm that Fabrice Muamba has been admitted to the heart attack centre at London Chest Hospital where he is currently in a critically ill condition in intensive care. No further information will be issued at this stage. The club has requested the media to respect his family's privacy at this time."
A packed White Hart Lane looked on with a worldwide audience watching live coverage on ESPN as the Trotters midfielder suddenly fell to the floor.
Confusion turned to horror as medics sprinted on to the pitch to begin resuscitating the young man. Players looked shocked and watched in disbelief as the former England Under 21 star was treated with a defibrillator for several minutes before being stretchered off wearing an oxygen mask and taken to hospital.
World Cup referee Howard Webb abandoned the game. As the message was relayed around the stadium with the score at 1-1, the fans applauded and chanted Muamba's name.
Premier League chief executive Richard Scudamore said: "The thoughts of the Premier League, its clubs and players are with Fabrice Muamba, his family and Bolton Wanderers. We would like to praise the players, match officials, coaching staff and medical teams of both clubs at White Hart Lane for their swift actions in attending Fabrice."
Manchester United star Rio Ferdinand wrote on Twitter: "Come on Fabrice Muamba, praying for you." England striker Wayne Rooney wrote: "Hope fabrice muamba is ok. Praying for him and his family. Still in shock." Muamba's team-mate Stuart Holden added: "Still praying for Fab, the guy is a fighter on and off the field. We love you bro."