On his way to becoming Bulgaria's all-time record goalscorer, seven-time footballer of the year and the country's most expensive player, it sometimes seemed as if Berbatov barely broke stride as he nonchalantly netted goal after goal.
Now approaching the twilight of his career, it's easy to see why the 36-year-old thinks this is a vintage year for football's over 30s.
"There are some players that are exceptions to the rules and they deserve a lot of respect," Berbatov tells CNN, extolling the virtues of United's Zlatan Ibrahimovic and Sunderland's Jermain Defoe, a pair of fellow thirtysomething strikers who have scored 15 and 14 goals in the English Premier League respectively this season.
Without a club since he left Greek club PAOK FC in June, Berbatov -- a $38 million signing for Sir Alex Ferguson's United in 2008 -- says he still trains as much as he did during his four seasons at the Manchester club, suggesting such a work ethic becomes a "habit."
If some players are guilty of switching off, the Bulgarian is adamant he'll never lose the spark he possessed as a hopeful teenager in his hometown of Blagòevgrad.
"This is the way of life," he explains. "You live it for 17 years. Not doing it seems strange."
Berbatov takes inspiration from the exploits of Ibrahimovic, 35, and Defoe, 34, and sees no reason why either should think about taking their foot off the gas.
Many believed Defoe's career in European football was over when he moved to Toronto in 2014 to play in Major League Soccer.
Instead, playing for Sunderland, the division's bottom side, Berbatov's former Tottenham teammate has scored as many league goals as Harry Kane, last season's Premier League top scorer.
"He's at that age where you look at a player and you think 'it's time to slow down' but he just loves scoring goals," says Berbatov of Defoe.
"He was such a professional. Just look at his body structure and the way he has carried himself.
"And then you have Zlatan. The legend. I think everybody looks at him scoring at the age he is for fun. It shows you it's not about age. It's the way you play football."
While some strikers carve a career from their blistering pace, it typifies Berbatov's more measured approach that he was unfazed when United boss Ferguson dropped him back to central defense during a cup tie against Leeds United in 2011.
Famed for his gossamer first touch -- he once unveiled a T-shirt after scoring saying "keep calm and pass me the ball" -- the Bulgarian didn't look out of place.
"Not many know this, but in training sessions I like to play in the center-back position sometimes," says Berbatov. "I think I'm good at that position and my father used to be a central defender.
"Some people don't realize that if you play in that position you can better understand how the defender thinks. Then, when you play as striker in official games, you start to think a different way. You need to be clever like that."
Suffice to say, United kept a clean sheet at Elland Road that evening.
Berbatov's ability to be "clever" proved invaluable throughout his career.
But he urges caution to those lauding the meteoric rise of 19-year-old Gabriel Jesus, particularly given some are writing off fellow Manchester City striker Sergio Aguero because of the immediate impact the Brazilian has made since his $33m arrival at City.
And with Jesus breaking a metatarsal bone in his foot this month, and consequently a doubt for the rest of the season, Aguero could yet get a chance to prove his worth.
"I don't like things like this," says Berbatov. "Sergio is a fantastic player and he has been doing this for maybe 10 years or more. Scoring goals, making assists and being one of the best.
"Some new player comes in and he's doing it for one game. You need to have more respect for a player who has done this all his career."
Even now, after waking up early to drive his children to school, Berbatov finds himself drawn back to the gym.
"It is my job and my hobby," he shrugs. "It's the way you carry yourself in life. You need to be a professional -- how you train, how you eat, how you sleep, where you go outside of football. You need to watch yourself in the mirror and say 'OK, I am still in shape.'
"I'd like to say I'm currently an active player because it is so difficult to stop. The older you get, the more you realize you have to enjoy it more and more."
With over 200 league goals for seven clubs since the turn of the millennium, Berbatov hopes the sun won't set on his career for a little while longer, though he's ambivalent about going to China -- should an offer transpire before their transfer window closes on February 28.
"I'd need to ask my wife," quips the Bulgarian. "I still feel great," adds Berbatov. "I am around the same age as Defoe and Zlatan so we'll see. As long as I feel good, I'll have the desire to play.
"The Premier League is in my heart. If I see an opportunity, I'll take it."