Despite the conditions being in their favour the Knights failed to take full advantage and Folau added his second just before halftime to close the gap to 12-10 at the break.
A Sandow penalty after the break levelled the scores but the Knights got their noses back in front with a Tyrone Roberts two-pointer.
A first try of the season for Bureta Faraimo gave the Eels the lead for the first time in the game after a Sandow kick took a fortuitous bounce over the head of Joey Leilua and into the grateful arms of the winger.
But the Knights hit straight back with a Dane Gagai try to level the scores and then roared back in front when James McManus went over the left corner.
However, Roberts was unable to add the extras and the Eels managed to keep themselves in the game and were rewarded with Peats' first try of the season with 13 minutes remaining.
The Knights tried manfully to attack, but the committed Eels defence held firm and they iced a deserved win when Peats got the final touch to a loose ball in the in-goal area.
Eels prop Richie Fa'aoso's long-awaited return to the NRL lasted just five minutes with the former Knights forward forced off with a concussion midway through the first half.
- AAP