Tru Plant Tigers had three unbeaten riders in stand-in skipper Jack Holder, Josh Pickering and Troy Batchelor.
They dominated from start to finish in front of a vibrant crowd who enjoyed the afternoon racing in the sunshine.
Holder admitted: “That was a good win and a good way to prepare for Thursday.
“I enjoyed it out there and all the boys got stuck in and got the job done.”
Boss Simon Stead warned Thursday will be a different story.
“We did the job but we can’t read too much into that,” he said. “Belle Vue will be a lot more problematic. They’re a super side and we know what to expect.
“I was delighted for Batch (Troy Batchelor). It wasn’t that long ago that we were talking about zero for him in a meeting here and now he’s gone through the card which is great for him and great for us.
“He’s had issues this year with his engines and things like that but he’s starting to make it work and I hope that can happen on Thursday.
“We need the backing of our brilliant fans on Thursday and I’m sure the atmosphere will be electric.
“It’s set up nicely, we can use tonight as valuable preparation but I also expect King’s Lynn to be a different proposition in 2022.
“It’s nice to see new blood in the sport like Alex (Brady) their managed and I look forward to locking horns with him next year.”
Thursday’s meeting is set to pull in a bumper crowd with online tickets selling fast but there will also be cash turnstiles available on the night.
SHEFFIELD 61: Jack Holder 15, Josh Pickering 13+2, Troy Batchelor 13+2, Danyon Hume 8+2, Adam Ellis 8+1, James Wright 4+1, Kyle Howarth r/r.
KING’S LYNN 29: Kasper Andersen 7+3, Ben Barker 7+1, Connor Mountain 4+1, Lewis Kerr 4, Thomas Jorgensen 4, Erik Riss 3, Richard Lawson r/r.