Premier League footballer Fabrice Muamba remains in a critical condition in hospital today after collapsing during an FA Cup tie.
The 23-year-old "remains anaesthetised" in intensive care at 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.
Today, club manager Owen Coyle thanked fans for their support, adding: "All our thoughts and prayers are for Fabrice and his family at this time."
A joint statement from the hospital and Bolton Wanderers read: "Fabrice Muamba remains in a critical condition in intensive care in the Heart Attack Centre at the London Chest Hospital.
"He was admitted to the hospital yesterday evening after collapsing at White Hart Lane, where he sustained a cardiac arrest during the FA Cup quarter final against Tottenham Hotspur.
"Fabrice received prolonged resuscitation at the ground and on route to the London Chest Hospital, where his heart eventually started working.
"As is normal medical practice, Fabrice remains anaesthetised in intensive care and will be for at least 24 hours. His condition continues to be closely monitored by the cardiac specialists at the hospital."
Bolton Wanderers manager Owen Coyle added: "Fabrice's family have asked me to pass on their thanks for the many, many kind messages of support from not only Bolton fans but also fans from clubs across the country and abroad.
"All our thoughts and prayers are for Fabrice and his family at this time. The family would also like to thank the media for respecting their privacy at this time."
Dr Iqbal Malik, a cardiologist at Hammersmith Hospital, told BBC Breakfast it was likely Muamba's collapse resulted from an abnormality he was probably born with that had not been picked up "despite the very aggressive screening programme that we do for professional athletes".
Data from London Ambulance Service showed a 25% survival rate once someone had suffered a cardiac arrest and been treated by ambulance crews, he added.
He said: "I think he's probably in a slightly better situation than that because what he got was immediate attention.
"The paramedics were there, the physios were there, and he got the defibrillator immediately and had the cardiopulmonary resuscitation (CPR) given to him immediately.
"That meant he's got the best chance of actually having his brain intact as well as having his heart rhythm problems sorted out."
Dr Malik said hospital staff would have to stabilise the heart rhythm, support the blood pressure and cool the body.
He added: "The only thing we can do once we've done all that is to wait and see whether he's going to start making some signs of recovery in the next 24 or 48 hours. The key actually isn't the heart at the moment, it's the brain."
He conceded the situation was like a "timebomb", adding: "What exercise doesn't do is suddenly make it happen when it wasn't going to happen before. Of course it will bring it out, putting a strain on the system is always going to be doing that."
Before the match Muamba took to Twitter to express his excitement over the tie.
Using the username fmuamba, he tweeted: "Just reach white hart lane. £COYW lets have it now."
Just hours later, the scene on the pitch recalled memories of Cameroon's Marc Vivien-Foe who collapsed and died during a Confederations Cup match in 2003.
Fellow players took to Twitter to express their shock after his collapse, including Arsenal and England midfielder Jack Wilshere, Manchester United star Rio Ferdinand, England striker Wayne Rooney and Muamba's team-mate Stuart Holden.
Tottenham forward Rafael Van Der Vaart, who was on the pitch when Muamba collapsed, wrote: "Terrible what happened with Muamba during the game. We're all praying for him."
Phil Brown, former assistant manager at Bolton Wanderers, who witnessed Muamba's collapse, described yesterday's scenes as "alarming".
Mr Brown told BBC Breakfast: "If you witness something like we witnessed last night it takes it to the other end of the spectrum. It's very hard to believe what you're seeing in front of your own eyes."
He added: "There are a lot of religious players and to see them all almost crouching down and dropping to their knees and praying, it was quite shocking, to tell you the truth."
Discussing the checks that players are subjected to, he said: "The screening processes that we use at the top level should be and can be sufficient to try and eradicate this, but there's that side of life you just can't cater for. You just don't know when it's going to happen."
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.
"The league would also like to commend the compassion shown by the fans of Bolton Wanderers and Tottenham Hotspur.
"We hope to hear positive news about Fabrice who is and has been a wonderful ambassador for the English game and the league at Arsenal, Birmingham City and Bolton Wanderers."
The Football Association (FA) also released a short statement, saying: "Our thoughts and prayers are with Fabrice Muamba and his family right now. A wonderful person."
Fans left flowers, shirts and scarves at Bolton's Reebok stadium close to the players' entrance and the location of the club's remembrance book.
Supporters arrived throughout the morning to leave tributes.
One message written on a card with a Manchester United emblem on it read: "Our thoughts and prayers are with you. One game, one family."
A Bolton flag was signed with the message: "Just get back to full health. Praying for you."
Two Bolton shirts were left at the scene, signed with messages of support.
An Easter egg was also left by one fan.