Both players play similar roles for their teams but Gueye presently has the most tackles in the Premier League (126) while Fred has completed just 28 tackles 17 league games this term.
A fortnight ago, Gueye outshone the Brazilian midfielder at Goodison Park as Everton cruised to a 4-0 victory over the Red Devils.
Following another impressive display at Selhurst Park against Crystal Palace on Saturday, Merson thinks the Senegalese star is superior to the £52 million signing, who has struggled to boost United’s top-four fight.
“I look at their players and I don't want to dig out Fred that he's not good enough for Manchester United,” Merson told Soccer Saturday on SkySports.
“The lad at Everton is 100 times better than him, Gueye's 100 times better than him.
“£52 million [For Fred], he's not like he was a free.
“I’m not a Man United fan, but I was embarrassed. It was cringeworthy [against Everton].”