The Chairboys scored early on through Matt McClure in their only meaningful attack of the game to steal the points in a real Devon smash and grab raid.
McClure - back after a Boxing Day ban - won the game in the 11th minute just seconds after Argyle striker Nick Chadwick had seen his shot on the turn cannon off a post.
They had to withstand concerted Plymouth pressure from beginning to end to claim the three points, leaving player-manager Ainsworth to reflect with pride on their backs-to-the-wall efforts.
"When things are going well and we're attacking well, the game becomes easy," he said.
"But, with the onslaught we had to stand up to - in the second half especially - I thought the lads were absolutely outstanding.
"In its own way, it's probably one of the best performances under me so far.
"We didn't attack as well as we can. It was a real team effort, a real Wycombe performance. The lads were superb.
"It's a tough place to come and win. I've not won many times in my career here. It's a really good scalp."