Fabrice Muamba remains in critical condition in intensive care
Bolton's Fabrice Muamba is critically ill and will remain in intensive care until at least Monday morning.
The midfielder, 23, is at the London Chest Hospital's heart attack centre after suffering a cardiac arrest during Saturday's FA Cup tie at Tottenham.
At 2030 GMT on Sunday the hospital said Muamba remained in intensive care where he is being kept sedated.
Bolton chairman Phil Gartside said: "I ask for everybody to keep Fabrice in their prayers and thoughts."
In a statement on the club's website, Gartside added: "The staff at the London Chest Hospital have been nothing short of exceptional and I would like to thank them all at this on-going critical time.
"The support that we had yesterday from Tottenham and our own fans was fantastic - the staff, the fans, the players and the officials at the game - it was unbelievable."
Speaking outside the hospital on earlier on Sunday, Bolton manager Owen Coyle said: "From our end, and on behalf of the family, we certainly want to say thanks to everybody.
"Everybody is praying for Fabrice which is very important and that has been a real source of strength to the family.
"We know it's such a difficult time for everybody involved, our thoughts are with Fabrice's family."
Coyle had earlier stated: "It's very serious. There's no getting away from that. God willing, he makes it through."
Bolton's Premier League game at Aston Villa on Tuesday has been postponed.
Medics spent six minutes trying to resuscitate the former England Under-21 international on the pitch after he fell to the ground with no other players around him.
The score was 1-1 when the quarter-final was abandoned after 41 minutes.
Earlier on Sunday, the hospital said in a statement: "Fabrice received prolonged resuscitation at the ground [White Hart Lane] and en route to the London Chest Hospital, where his heart eventually started working. His condition continues to be closely monitored by the cardiac specialists."
Members of Muamba's family and his fiancee attended the hospital on Saturday night.
In a statement released on Sunday Spurs chairman Daniel Levy said: "Our thoughts are with Fabrice's family and Bolton Wanderers, and we are all willing him to pull through. Events such as this put everything into perspective.
"We are immensely proud and grateful to the medical teams at both clubs, their response was immediate and professional. Our thanks also to both sets of fans for their support and behaviour.
"Too often we read the negatives about football and yet last night, at a time of intense emergency and uncertainty, we saw the true humanity and empathy of the footballing family."
Spurs manager Harry Redknapp added: "Football is the last thing on anyone's mind when an awful situation such as this happens. All we are thinking about now is Fabrice and his family."
Medical staff gave mouth-to-mouth resuscitation to Muamba, who was born in Zaire (now Democratic Republic of Congo) but moved to England aged 11, and tried to revive him with a defibrillator.
In total, six medics were treating the player, who joined Wanderers from Birmingham in 2008 and has made 148 appearances for the club.
Both sets of supporters chanted Muamba's name as he was taken off the pitch on a stretcher. ESPN, who were broadcasting the match, reported that he was not breathing as he was taken into the tunnel.
Referee Howard Webb called the visibly shaken players off the field after consulting with Coyle and Redknapp.
After Muamba had been taken to hospital, the match was abandoned.
The former Arsenal midfielder was accompanied in the ambulance by Coyle and club captain Kevin Davies.