Crisis-club Vale left their troubles behind them out on the pitch as they surged into an early two-goal lead but later lost impetus, irritating their hard-to-please manager.
"We'd set the tempo, but after about 30 minutes we sat off and let them play a bit," said Adams.
"For the first 25 minutes of the second half it was painful and we couldn't get going.
"I was delighted with some of our play, but disappointed with some of it too.
"We're going to get bigger tests than that as it will take Barnet time to find their feet under their new manager. We are going to have improve on certain aspects of our game."