It is a tale of love and dedication scripted in the heart of Abu Dhabi
The Belgium international, 24, scored nine goals in his first nine appearances against West Ham for former team Everton before the east London club finally kept him at bay in a 0-0 draw last April.
Lukaku scored a consolation goal as United lost 2-1 to Real Madrid in the UEFA Super Cup in the Macedonian capital Skopje on Tuesday and his team-mates have been impressed by what they have seen in pre-season.
"Lukaku has done a great job with the clubs that he has been at," said United right-back Antonio Valencia.
"I am a kid next to Romelu. He truly is strong. I have seen him work on the field and in the gym.
"It's truly incredible to see his strength, power and the intelligence he possesses. We hope it is a good year for him and the team."
Lukaku, a £75 million ($97.3 million, 82.4 million euros) capture from Everton, could be one of three players making league debuts for United on Sunday along with Victor Lindelof and Nemanja Matic.
United manager Jose Mourinho used a conservative 5-3-1-1 system against Real Madrid, but is likely to be bolder against West Ham, who have not won at Old Trafford in 10 years.
Mourinho has no new injury concerns, with Marcos Rojo, Luke Shaw and Ashley Young his only long-term absentees.
Defenders Eric Bailly and Phil Jones return to contention after sitting out the Super Cup through suspension.
Having led United to League Cup and Europa League glory last season, Mourinho's challenge for the new campaign is to turn them into title contenders.
"The Premier League is what you all know," Mourinho said on Friday.
"I'd say seven teams to fight for the title and 20 teams to fight for the victory every weekend, every match.
"The club are also what you know. We are involved in four competitions and step by step, match after match, we are going to fight."
United trailed home in sixth place last season, 24 points below champions Chelsea, and have finished in the top four just once since Alex Ferguson retired as manager in 2013.
Javier Hernandez was there as the rot set in under David Moyes and he will make his Old Trafford return on Sunday after joining West Ham from Bayer Leverkusen in a £16 million deal.
The 29-year-old Mexican, known as 'Chicharito' (Little Pea), was a crowd favourite during his five years at United, scoring 59 goals for the club and playing a part in two league title successes.
He admits it will be a strange experience to line up at his old stomping ground in the colours of a different team, but says he will not allow sentiment to cloud his focus.
"It's my old club with my old fans and my old stadium, so probably I cannot celebrate," he said.
"But as well it would be my first goal with my comeback with a club that has a lot of confidence in me."
West Ham manager Slaven Bilic has reshaped his squad extensively since last season's 11th-place finish.
Former Manchester City pair Joe Hart and Pablo Zabaleta and star signing Marko Arnautovic, a £20 million recruit from Stoke City, could all make their competitive debuts on Sunday.
Left-back Aaron Cresswell and captain Mark Noble are expected to shake off injuries, but Cheikhou Kouyate, Manuel Lanzini, Michail Antonio, Andy Carroll and Diafra Sakho are all sidelined.
It is a tale of love and dedication scripted in the heart of Abu Dhabi
The event brought together key players in the polo community to celebrate a successful season and honour outstanding achievements
In the first two days after the torrential rain on Tuesday, around 1,244 flights were cancelled
There has been fear that decades of enmity between the two could spill over into all-out war
The leading hypermarket chain has implemented additional measures to ensure sufficient stock availability for shoppers
Thousands of personnel deployed to clear accumulated water, clogged drains, and fallen trees
Areas such as Abu Shagara, Al Qasimiya, King Faisal Road, Al Mahatta, and Majaz have been particularly affected
The Ministry of Foreign Affairs reiterated its call on the United Nations and the UN Security Council to fulfill their responsibilities