Top scorer Jake Hyde gave the Bees a 21st-minute lead but Argyle hit back to win 2-1 and move off the foot of the League Two table and frustrate Davids.
"It was a very bad result but the team won that wanted it the most," he said. "They didn't play much better than us but they really wanted it more than we did, that's my opinion.
"I think they did stop us playing a little bit. The thing is that some players were not in the right shape today and you saw that when we came out passing, we were immediately dangerous and it also resulted in a goal.
"One of the reasons we didn't do well is because the majority of the players didn't do what they normally do so they have a big problem.
"Maybe they were tired maybe they weren't, I don't know, but what I saw was a team that wanted it more than we did.
"Jake Hyde had to come off at half time because he was injured and so we had to make some changes and we really have a young squad but at the end it still depends on determination.
"We didn't give Plymouth many chances but we didn't play and if you don't win the second balls it's going to be a hard game."