Bentley played skipper Will Haining just in front of centre-backs Chris McCready and Nick Fenton to nullify Vale's potent forwards Tom Pope and Lee Hughes.
The tactic worked well and Lewis Alessandra completed a smash and grab raid with a second-half winner.
Morecambe held on despite having defender Andrew Wight sent off 18 minutes from time.
"It was a terrific win against a fantastic team with a very good manager," he said. "I hope Vale go up.
"I watched them a couple of times and knew we had to stop the supply to the front two as much as possible. We worked very hard in training on how to do that and it's come off for us.
"The game could have gone either way and fortunately the result has gone for us.
"We had to ride the storm, especially after we went down to 10 men, but the lads have defended magnificently, Barry Roche has made some good saves and I'm very proud of all of them.
"The plan was to hit Vale on the break and we've managed to do that. We had two or three other promising situations before we scored and Lewis tucked the ball away well.
"We've got a great spirit in the group. All I ask of them is they give everything for the shirt and they've certainly put a shift in."