As for the Red Devils, they were heavily expected to sign Morata only to swoop for Lukaku, leading Chelsea to agree terms with Los Blancos for the Spaniard's signing in a deal worth €80m (£70.7m, $92.1m) plus add-ons.
Much debate has been focused on which forward will be the better signing for both clubs, but former Liverpool midfielder Murphy believes Lukaku is the more dangerous player.
"Centre-halves generally would rather play against Morata rather than Lukaku, because he's more manageable in terms of his physicality," Murphy told talkSPORT. "He's not the quickest. He's got great movement and he's a good finisher and quite reliable too, while people do doubt Lukaku's reliability."
"But in terms of a match winner, someone who can bully the defence, run in behind, hold the ball up, climb over players and head it, Lukaku on his day is hard to stop."
However, despite casting doubts on his goals-to-game ratio throughout his career, Murphy is confident that Morata will score goals, especially if he is first choice at Stamford Bridge.
"Morata is walking into a very good side and will score goals, for sure," Murphy added. "To hit the ground running and hit 20 in his first season – that takes some doing."
"But his goals-to-game ratio is quite low in comparison to Lukaku, but that's because a lot of his appearances have been off the bench or starting when he hasn't played for three or four weeks.
"It's hard to judge strikers that way. But I think he will play, I think he'll be first choice at Chelsea. And he certainly has got tremendous movement in the box, so scoring goals won't be an issue for him."