Harper had his best game of the year against the Warriors last week, pulling off one of the try savers of the season to hold up Jack Murchie over the line.
The win over the Warriors came in contrast to his outing against Cronulla in April, where he was hooked on halftime by coach Des Hasler as the Sea Eagles trailed 32-0.
In one of the most intimidating 40 minutes of football in years, Harper's opposite number Talakai scored two tries, set up another two, broke the line three times and busted eight tackles.
Hasler pointed to the 23-year-old's battles with a bad bout of COVID-19 as an excuse but Harper would have none of it.
"I'm not going to lie, I was f***ing horrible that night," a brutally honest Harper said.
"I can use the COVID excuse because I came back on the Monday … but at the end of the day, I didn't perform.
"I don't really care what people say or anything, it's more what I know within myself, and I know that wasn't how I play."
Harper was dropped the following week by Hasler, but worked closely with Manly mindset coach John Novak.
He returned against Wests Tigers a fortnight later, and then starred against the Warriors with his try-save in defence as well as a line break to put Rueben Garrick over in attack.
"It was pretty hard, to be honest, for the first few days. I didn't get picked the week after but it was understandable," Harper said ahead of Sunday's clash with Wests Tigers.
"But it's not what happens, but how you react.
"I'm just glad the boys around here definitely had my back and that's helped me get through it along with my missus at home.
"l'll give Johnny Novak a lot of credit. He helped me with the mental side of things and getting ready and prepared.
"Everyone can try do things for you, but it comes down to you and how you want to react to things."
Harper does not want to hide behind COVID-19, but it is worth noting his lead-up to the Cronulla game in round seven.
He was bedridden for part of the week before and lost 6kg before coming out of isolation three days before kick-off.
"The last month-and-a-bit has been about getting back and putting my size on," Harper said
"Dessie was good about it. He understood, and I also understood that I needed to go back and work on a few things and get some size on."
