The 24-year-old has been in impressive form for his Portuguese club during the 2021-22 campaign, scoring 14 times and registering five assists in 24 appearances in all competitions.
A recent report claimed that Liverpool were nearing a £60m deal for Diaz, with Porto open to selling the Colombia international during the January transfer window.
However, according to Record, Man United are 'paying attention' to the developments, and the Red Devils could yet win the race for his signature.
The report claims that Newcastle United are also keeping an eye on the situation, with the Magpies becoming one of the richest clubs in the world due to their recent takeover.
Diaz, who largely operates as a left-sided forward, has scored 39 goals and registered 18 assists in 121 appearances for Porto since arriving from Atletico Junior in 2019. body check tags ::