Bennett leapt off the front of the main group alongside the best climbers in the race - Wout Poels, Richie Porte and Michael Woods - and built a solid gap, but Bevin hunted them down on the descent to remain in control of the race lead.
Bevin said it was an extremely tough day, but was ecstatic with his efforts.
"I knew I was going to give away a bit to the climbers going up [Corkscrew]. I was fortunate I had a couple of guys who didn't have a rider in front [to help the chase], and I just rode," he said.
"As soon as I hit the wind, I was going to ride to the finish, and obviously that gave up a bit of energy for the sprint, so it was unfortunate to give up a bit of time to Daryl. But hey, if you told me I'd come away with second on the stage and still with the jersey, that's better than the best-case scenario from what I was concerned."
Bevin should safely keep the leader's jersey on tomorrow's sprint stage, before the race ends with an ascent of Willunga Hill - a 3.6 kilometre climb that Porte has won for the last five years running.
However, Bevin has a 21 second buffer over Porte, and he knows it's going to come down to his performance on that final climb as to whether he can maintain his lead over Porte, Impey, and potentially, Bennett.
"I've got a nice little buffer over [Porte] now, so it's about managing both parties, and trying to come away and win this bike race."