According to reports, the man in his 60s was taken ill around 20 mins before kick-off, received swift medical attention and was rushed to hospital.
A statement on the club's website confirmed on Friday (AEST): "It is with great regret that Liverpool Football Club can confirm that a supporter who was taken ill ahead of last night's fixture against Benfica has sadly passed away."
It is with great regret that we can confirm that a supporter who was taken ill ahead of last night’s fixture against Benfica has sadly passed away.
— Liverpool FC (@LFC) April 14, 2022
The thoughts of everyone at the club are with the supporter’s family, loved ones and friends.
In addition, a club spokesperson said: "First and foremost, the condolences and the thoughts of everyone at the club are with the supporter's family, loved ones and friends.
"We would like to thank the emergency services for their heroic efforts in providing urgent care and our appreciation to our medical professionals, stewards and all supporters in the vicinity of the incident for their assistance."
A statement released to the media by Merseyside Police confirmed the man's next of kin have been informed.