Mancunian Chisnall graduated from United's youth academy and represented United's senior team between 1961 and 1964, scoring 10 goals in 47 games, before joining Liverpool for a fee of £25,000 in April 1964.
We are deeply saddened by the passing of Phil Chisnall.— Liverpool FC (@LFC) March 4, 2021
The thoughts of everyone at Liverpool Football Club are with Phil's family and friends at this sad and difficult time.
Rest in peace, Phil Chisnall 1942-2021.
United posted a tribute on social media: "We are saddened by the passing of our former forward, Phil Chisnall.
"Phil was a product of our famed youth system and represented the club during Sir Matt Busby's tenure. Our deepest sympathies are with his loved ones."
A United club statement read: "Matt Busby, Bill Shankly and Alf Ramsey were three wise men who knew a thing or two about assessing rookie footballers and they all agreed that in the early-to-middle-1960s, inside-forward Phil Chisnall was potentially one of the best in the land."
Former Liverpool manager Shankly had hailed the forward on his arrival at the club, saying: "Phil can do unusual things with the ball, he might be something special."
Chisnall made his Liverpool debut in the Charity Shield four months after joining and opened his account in a European Cup victory at KR Reykjavik.
However, his time at the club was short-lived as he scored only two goals in nine appearances. His final game was the first leg of the 1965-66 Cup Winners' Cup semifinal against Celtic.
Chsinall then joined Southend United before ending his playing career at Stockport County.