Before returning to Chelsea, Romelu Lukaku turned into the striker Manchester United thought they had signed - and was the one that failed to set Old Trafford alight.
Lukaku lost the bulk and the brawn, but none of the goalscoring ability that lay dormant at Old Trafford to this day.
The numbers speak for themselves.
He was the fastest to reach 20 goals for Inter Milan, needing just 29 games, after he signed in 2019 from the Red Devils.
For comparison, the great Brazilian Ronaldo needed 31 matches, Hernan Crespo 36 and Christian Vieri 38 to reach the same mark.
In the 44 games he played in the 2019-2020 season he scored 30 goals, helping Inter to their first Serie A title in 11 years, winning the league's MVP award in doing so.
And was all been done by shedding more than half a stone in just 12 days.
United and Lukaku failed to realise the reason he was so bulky was that his digestive system had been 'malfunctioning', according to The Telegraph.
The results of a new diet and conditioning programme were clear when Lukaku took off his shirt and hung it on the corner flag after scoring the final goal in the 4-2 win over Milan in February.
Look at his waistline.
None of the bloat that was apparent at United, where he still scored 42 goals in 77 starts, is there any more.
The definition in his arms was clear as he kissed the shirt of the club that gave his career a real purpose again.
In fact, he resembled the Lukaku at Everton, with an overall smaller frame.
It was clear the jibes about his physique riled him.
Gary Neville called Lukaku 'unprofessional' after he admitted he turned up to United's pre-season overweight at 16st 3lb.
Neville blasted: "He admitted he was overweight! He is over 100kg! He's a Manchester United player! He will score goals and do well at Inter Milan but unprofessionalism is contagious."
SunSport told you Lukaku was shown the exit door after being 9lb overweight at United.
But he said a new diet of fish, sweet potatoes, pasta and raw vegetables had worked wonders.
A new playing formation that suited him, a coach in Antonio Conte who knew how to get the best out of him - just like he currently does at Tottenham - and closer attention to his body and his needs.
But unfortunately for Lukaku, Conte departed after winning the league in Italy amid a row over the club's transfer policy.
In a farewell post online, the striker hailed his ex-boss and referenced the physical and mental turnaround the Italian helped mastermind.
Lukaku wrote on Instagram: "2014 we spoke for the first time and we have had a bond ever since.
"We had many moments to work together but only god knows why it never happened earlier.
"You came at the right time and basically changed me as a player and made me even stronger mentally and more importantly we won together!
"Winning is and it’s all that matters to you and i’m glad that i have had you as a coach.
"I will keep your principles for the rest of my career (physical preparation, mental and just the drive to win...) it was a pleasure to play for you!
"Thank you for all what you did. I owe you a lot.."
Hardly groundbreaking ideas. These are things United could surely have provided easily, too.
How, now, they must be kicking themselves. These are certain lessons that could also be learned by Chelsea, where he struggles once more.