Gillingham narrowly saw off Cheltenham on the opening day thanks to Lewis Montrose's first-half strike.
Chris Whelpdale went close for the hosts before Montrose gave them the lead after reacting quickest to Jack Payne's deflected effort.
After the interval Danny Andrew sent a free-kick just wide for the Robins as they got back into the game.
Gills sub Luke Rooney saw red late on for a bad challenge on Brian Smikle but the hosts held on.
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Gillingham manager Andy Hessenthaler told BBC Radio Kent:
"Nice to get off to a winning start. We didn't really get our passing game together but at times you have to grind results out.
"They came and made it very difficult for us. To keep a clean sheet and three points, we're delighted.
"We're delighted for Lewis Montrose. He said he could get goals and he did that today.
"Second half they played from back to front quickly and made it difficult for us. We're not going to throw negatives at them, but you have to give the opposition credit."
Cheltenham Town manager Mark Yates told BBC Gloucestershire:
"I thought we were the better team and very unlucky not to get anything from it.
"We had a couple of shots on the break but we dominated in the second half but we fell into the trap of just slinging it into the box when we had that extra man.
"But overall I'm pleased with the performance and the effort and some of the football we played."