But substitute Dean Windass intervened right at the end and Adams, still looking for his first Fratton Park win as a manager, said: "I think it's a mental problem for us.
"The crowd here are fantastic for driving the team on, which is great if you are 0-0 or a goal down. They really motivate the team.
"But what the players need to do is not get caught up with that and learn to win home games 1-0 or 2-1 instead of going for three, four and five.
"We need to keep the ball a little bit better, not turn it over so easily and lock up games when we are ahead.
"Our centre-half Sylvain Distin is unbelievable. I love him but I looked up and saw him out on the left wing once and I don't think he would have done that away from home."
Adams admitted: "John Utaka's miss after we went 2-1 up was probably crucial in the end and we could have had it wrapped up in the first 30 minutes after starting so well.
"Glen Johnson's goal deserved to win the match but if I think about it I'm delighted we've now gone three games unbeaten and delighted with another point today in the current climate of the Premier League.
"You just have to keep picking up points."