Padraig Amond's first goal for the Shrimps seven minutes from time earned Bentley's men their second successive home win and he praised his side's spirit after recording their first ever victory over Plymouth.
Argyle took the lead through a Reuben Reid penalty when Morecambe skipper Mark Hughes was adjudged to have hauled down Marvin Morgan but the home side equalised almost immediately through their talisman Kevin Ellison.
Plymouth went close to taking the lead in the second half before Amond produced a superb finish to volley home the winner seven minutes from time.
Bentley said: "It was a poor game and we were nowhere near our best but I have forgotten how many times I have come out after a match wondering how we have lost when we deserved something.
"It is all about the end result and I'm delighted that we got that because it showed that we can do the ugly things well when we have to.
"The lads showed great determination and stuck with it. We were a bit flat at first and we had to weather an early storm and gave away a sloppy penalty.
"But we responded magnificently and equalised in the next attack which was a marvellous response. We were much better in the second half and the lads really stuck with it and I was delighted to see Padraig get the winner with his first goal for us.
"After two defeats in our first three games two home wins in a row makes things look much better and it has definitely given us something to build on."