However, the former Red Devils striker does not believe Lukaku is yet at the level of Tottenham forward Harry Kane.
It was announced on Saturday that United have reached an agreement with Everton concerning the transfer of Lukaku to Old Trafford, subject to a medical and personal terms.
Should the deal go through, the Belgium forward will link up with the Red Devils having scored 71 goals for the Toffees over the last three seasons.
He is one of the most prolific goalscorers in English football, but Dublin believes he is still ‘half a notch’ behind Kane, who has won the last two Premier League Golden Boots and has netted 94 goals in the same timeframe as Lukaku’s 71.
Speaking to talkSPORT, Dublin said: “As a centre-forward, I don’t think there’s a box he (Lukaku) doesn’t tick.
“Harry Kane, for me, ticks every single box. Lukaku is maybe just half a notch off Harry Kane.
“I believe Lukaku is the biggest prospect in the Premier League, and can get better – a lot better.”
It was expected Lukaku would leave Everton for Chelsea this summer, not United
His relationship with Jose Mourinho was said to be rather fractious given their shared spell at Stamford Bridge, but Dublin believes both men will get the best out of one another at Old Trafford.
“Maybe he wanted a change,” Dublin said, when asked why Lukaku did not return to Chelsea. “Maybe he was thinking ‘I was there for a while and you didn’t want me then’.
“Mourinho must have seen a difference in him, a change in him. I don’t think Mourinho is stupid enough to say ‘I’ve had him before; I’m not going to have him again’.
“He just wants to win, and I think Mourinho will find a way to get the best out of Lukaku, as Lukaku is a very, very good centre-forward. Supply him, and he will score goals.
“In a Man United shirt he’ll get more chances than at any other club in the Premier League, so now all he’s got to do is get his numbers up and he’ll be one of the best in the world.”