United overlooked Austin, despite their lack of goals, and the 26-year-old ended up moving to Southampton from Queens Park Rangers instead.
Holloway believes that Austin shares a lot of similarities with Alan Shearer, and he has backed the powerful forward to be a major hit at St. Mary’s.
"In the last 18 months, apart from Harry Kane, I haven't seen a better centre-forward than Austin in English football," Holloway said. "Remember, he scored 18 goals in the Premier League for a team that finished bottom. If you can do that, you've got to be pretty special. What I love most about him is that he hasn't sulked - he always tried his hardest for QPR.
"Manchester United can't score for toffee. Why didn't they go in for him? I'll tell you why. Austin's not a fashionable signing. For some reason, Austin doesn't fit the criteria of one of the big wigs to buy him. Some players are deemed not fashionable enough to play for certain clubs. It makes me sick.
"Well done to Ronald Koeman for looking through all that nonsense.
"There isn't much difference between Alan Shearer and Austin. Shearer perhaps developed a bit quicker as a youngster, but they are both top-class old fashioned centre-forwards. Wherever Austin has been, he's scored a goal every two games. That's a phenomenal record. I'm chuffed for him."
Austin has the potential to prove to be a huge bargain for Southampton, who managed to buy him for just £4 million from QPR - according to a report in the Daily Mail.
The striker has wasted no time making an impact with Ronald Koeman’s side, either.
Austin came off the bench to score the winner against United, to cap his debut off in memorable fashion and pile the pressure on Louis van Gaal and his squad.
Austin netted 18 times for QPR in the Premier League, and Saints will be hoping that he is similarly potent this time around as he bids to fire them up the table in the months ahead.