Kieran Agard scored the 75th minute winner which keeps Rotherham third and two points clear going into the final match of the season.
Agard applied the deft close-range finishing touch after skipper Johnny Mullins headed down Joe Skarz's 50-yard free kick into the six yard box.
Evans said: "It was another hard-earned win. We keep saying there are 46 battles in this league and credit to Plymouth I thought they were terrific in every aspect, from the first to last minute.
"We dug in, we worked hard and we just stayed true to our principals and believed that if we did that we would make a chance or two.
"Early in the second half we have missed a couple of chances in quick succession, young Kieran and Alex Revell, and then Kieran pops up and gets us a goal, which he has done on more than one occasion and then you have to defend heroically and we did that.
"We were checking the results during the second half and at one stage we were going to bring Dan Nardiello on but within a few seconds we got the goal.
"He was desperate to get on the field of play, probably 90-plus per cent but not quite 100 per cent.
"We had real strength and togetherness and I can only say positive things about these players. We always maintained since as far back as August that I could see this League Two campaign going to the wire, to the last day and here we are going to the last day."