The Belgium international was initially linked with a return to Premier league champions Chelsea earlier in the summer transfer window.
However, Manchester United managed to hijack Chelsea’s proposed deal to sign Lukaku and secured the striker’s signature in a £75m deal from Everton last month.
Lukaku scored his first competitive goal in a 2-1 loss to Champions League holders Real Madrid in the Uefa Super Cup last week.
The 24-year-old continued his goal-scoring run with a clinical close-range finish in the first half to give Manchester United a 1-0 lead at Old Trafford.
Lukaku doubled the home side’s advantage from a set-piece to make the perfect start to his Old Trafford concerns and dispel concerns about his ability to lead the line for a top club.
Manchester United legend Ferdinand wasted no time taking to Twitter to hail Lukaku’s performance in his debut at Old Trafford as a Red Devils player.
Ferdinand wrote on Twitter: “The beast has landed !!! #MUFC @ManUtd”
He added: “And another…… @RomeluLukaku9 🔥⚽️ that’s why he was my no1 on Best Signings this summer!!!”
Lukaku scored 25 times in 36 games in the Premier League last season to finish behind Tottenham Hotspur rival Harry Kane in the goal-scoring charts.
France striker Anthony Martial scored Manchester United’s third goal before Paul Pogba wrapped up a 4-0 victory over the Hammers.
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