"When you lose your dummy half and your rock in the middle of the field, it does throw the dynamic out a bit and we didn't adjust ourselves or cope as well as we should have," said Kearney.
"[But] they showed courage to come from behind ... they could have let it drift away from them."
Luke, who injured himself kicking a conversion, and Mannering are not expected to be long-term injuries and may be available for Friday night's clash with Melbourne at Mt Smart.
At times yesterday, it felt like no much has changed with the Warriors mixing sweet and sour, and inexplicable errors combined with sublime touches. But instinct indicates there is plenty of improvement in this team and there will need to be, as they will face much stiffer tests in 2017.
It's a win, which breaks an opening-day hex, dating back to 2009.
The Knights were impressive yesterday, but had only four players with more than 100 NRL games and the inexperience of their roster showed. Other teams may have put the Warriors away in the second half.
"We didn't get a great deal of field position and I knew if we got some time down there, we would create some opportunities," said Kearney. "It was just a matter of digging ourselves too big a hole."
The Warriors made a nervy start, with errors galore in the first 20 minutes, including a mistake on the first tackle of their first set.
But they came alive at the end of the half, with four tries in the space of 14 minutes, including a hat-trick to David Fusitu'a.
His second try will be one for the highlights reel, courtesy of a spectacular mid-air "alley-oop" from Tui Lolohea, who caught the ball outside the touchline, before passing basketball style inside to the centre.
His third was also impressive - a one-handed flick pass from Shaun Johnson - and Tuivasa-Sheck showed his prowess to set up Solomone Kata.
Things unravelled in the second half, with two tries to winger Nathan Ross taking the Knights into a 22-20 lead. It could have been worse - Trent Hodkinson hit the uprights with two successive conversion attempts - before Tuivasa-Sheck's slashing break, which eventually led to Hoffman's vital try.
Warriors 26 (D Fusitu'a 3, S Kata, R Hoffman tries; S Johnson 2, I Luke goals)
Knights 22 (P Matautia, J Stockwell, N Ross 2 tries; T Hodkinson 3 goals)