“I have supported Chelsea as a kid and now to be back and try to help them win more titles is an amazing feeling.”
Less than 12 months later the Belgium striker is leaving the club in arguably one of the most expensive transfer mistakes in Premier League history.
Lukaku’s return to Chelsea on a five-year deal cost the Blues a club-record £97.5m, but he departs 10 months later on an initial loan deal having failed to make the impact both he and the club would have hoped for.
His signing was supposed to turn Chelsea into Premier League title contenders so how, and why, did it all go so wrong?
A move that should never have happened?
When Chelsea announced the re-signing of Lukaku it appeared they had secured the final piece of the jigsaw.
The 29-year-old had just enjoyed a stellar season at Inter, scoring 24 league goals and providing 11 assists as the Italian side ended a decade of Juventus dominance to win the Serie A title.
Lukaku also had unfinished business at Chelsea. He first joined them as a teenager from Anderlecht in 2011, but left three years later after failing to score.
“I’m happy and blessed to be back at this wonderful club,” Lukaku said at the time of his return to Stamford Bridge.
“It’s been a long journey for me. I came here as a kid who had a lot to learn, now I’m coming back with a lot of experience and more mature.”
The motivation and the pedigree was there, while Chelsea desperately needed a striker. It was a move that made perfect sense.
He could not have hoped for a better second debut as he scored in a 2-0 win at Arsenal on 22 August, but it did not take long for things to unravel.
After netting twice in a 3-0 win against Aston Villa on 11 September, Lukaku did not score another Premier League goal until 26 December.
“He was seen as the final piece in the jigsaw,” Chelsea fan and CFCU fanzine writer Tim Rolls told BBC Sport.
“People were excited. We had fast wide players and he was the piece that would complete the jigsaw. He was expected to make us contenders.
“Initially he looked the business, but for whatever reason it tailed off very quickly.”
Injuries and a bout of coronavirus did not help, but on the pitch he showed little of the strength, hold-up play and finishing ability that helped him score 47 goals in two seasons at Inter.
Despite Lukaku’s words on his return, the striker at times appeared unmotivated.
An interview with Sky Italia in December seemed to confirm that view as he said he was “not happy” with his role at the Blues.
“Item [the return to Inter] has been Lukaku-driven. He made it very clear in that interview he gave,” Italian football expert James Horncastle told BBC Radio 5 Live.
“I think the subtext of that was that leaving Inter wasn’t his decision. It was because of the financial stresses and strains that the club was under at that time.
“The circumstances of his departure played on his mind a lot and left him confused.”
The glove that just did not fit
In that Sky Italia interview, Lukaku made it clear that much of his unhappiness at Chelsea stemmed from how he was utilized by manager Thomas Tuchel.
The German coach swiftly rejected the claim that his system did not play to Lukaku’s strengths, yet still he struggled to make an impact when he did play.
When Chelsea beat Crystal Palace 1-0 in February, Lukaku managed just seven touches of the ball – the fewest for a player featuring in the full 90 minutes of a Premier League match.
“It’s not about the system,” Tuchel said afterwards.
“There is no change of system because it’s the same attacking structure. We always attack in a 4-1, it’s just for the build-up sometimes we are in a 3-2, sometimes in a 4-1. For him, it changes nothing.”
Despite his struggles Lukaku finished last season as Chelsea’s top scorer with 15 goals in all competitions, but given the significant fee paid to sign him, Tuchel and Chelsea fans expected him to contribute more.
“Because he cost so much he has to be one of Chelsea’s worst signings,” added Rolls.
“When we bought Diego Costa he made an immediate impact on the team. He was a leader, but Lukaku was almost the opposite.
“The other forward players were maybe looking for him to lead and he didn’t. We were left rudderless.”
Lukaku had also been linked with Manchester City last summer and Micah Richards believes that it would have been the best move for him.
“I think if Lukaku was in Manchester City’s team he would score goals,” the former City defender said on The Monday Night Club last month.
“I think that’s the difference – it’s the system.”
Will Inter return reignite Lukaku?
Inter were unable to defend their title last season and finished second to rivals AC Milan, although scoring was not a problem for Simone Inzaghi’s side, with no team scoring more than Inter’s 84 league goals.
But the Italian side will see the return of a player who scored 34 and 30 goals in his two previous seasons at the club as the move that will give them the edge over their rivals in the coming campaign.
Lukaku turns 30 next year so time is no longer on his side, but a happy Lukaku is a scoring Lukaku and it is clear this will be a move that suits all parties.
“There were murals of Lukaku when he was last at Inter,” Horncastle added. “He was voted the best player in Serie A in a year when [Cristiano] Ronaldo was the top scorer – that’s how good he was.
“It’s clear that he felt he played his best football at Inter, that they understood him, that he understood them.
“He should never have left.”