It was impressive stuff, especially given the mental baggage he could have carried.
"I worked on it throughout the week," said Kosi. "Everybody knew what happened in the last game against Melbourne so I had to come in and do my job. Initially when they told me I was gonna play it kind of did (play on my mind) but I knew I had to flush that. I had to block the noise and just focus on what I do best."
It was quite a personal redemption, given what Kosi went through after the Anzac Day episode.
He admitted he started to wonder if he was cut out for NRL level – "there was a little bit of doubt in myself in after that game" – as he processed the performance, but a heart-to-heart with then-teammate Matt Lodge offered some crucial perspective.
"I was tearing up and Lodgie took me away and we had a coffee and a chat about it", says Kosi. "I put all the weight of that game on my shoulders. I felt like I was the one to blame for the loss because it's due to my errors and stuff like that but he was saying not everything was my fault, it was a shared performance. He reassured me that I've got to keep working hard."
That meeting was important – "I felt like I kinda reset myself" – but Kosi wasn't seen again in first grade for almost three months, as he rebuilt his confidence and game in reserve grade.
"I had time to reflect on things," said Kosi.
Injuries led to Kosi's return against the Parramatta Eels two weeks ago – where he was solid – before the selection to face the Storm when Jesse Arthars was ruled out.
"I needed to have my [mind] on the job," says Kosi. "I had to focus real hard because you can't fall asleep on good teams throughout the game."
In only his 11th NRL game, Kosi looked sharp from the onset, with some strong carries and was confident under the high ball, as the Storm peppered his flank. The 107kg wing took his opportunities well, with tries in the 20th, 33rd and 63rd minutes.
Coach Stacey Jones couldn't hide his admiration for the Mangere East junior.
"He was outstanding," said Jones. "From where he was when we last played [the Storm], he's come a long way. He's worked hard on his game. Hopefully this is the start of suddenly something good for Ed and the club."
The night was doubly special for Kosi, who made his NRL debut in round eight last year, with his father and girlfriend among the 18,395 crowd.
"It was good to kind of think about them while I was playing, supporting me throughout the game," said Kosi. "[And] three [tries] in my first game at Mt Smart topped it off for me."