Voss said the players' "composure of thinking" and inability to reverse "20-minute" periods - like North Melbourne's seven-goal first term on Saturday night - needed work.
"It's up to me to be able to teach them and ensure that when they get in those positions, they can think through it," he said after the Lions' one-point loss at Etihad Stadium.
"At this point in time, we're not executing that. I have to be able to sit here and say that's not good enough from my end. I've got to be better than that."
Voss said his players were capable of launching a counterattack, but their inability to stem a flow of goals was hurting them.
"You look at the stats and they kicked seven goals in the first quarter and five for the rest of the match," he said.
"Clearly we were able to arrest that at a point in time. We stabilised the game in the second quarter but in that patch they got away from us.
"We knew what they'd be like post their loss last week. We knew they'd come out and have that competitive desire."
Voss addressed his players in a lengthy post-match meeting but said there was no point in berating them.
"They'll learn from it," he said.
"It's hard to be able to sit in there and say, 'Look guys, there's three quarters and 10 minutes where you're great and we're able to get our hands on the footy and even-up the statistics, even get a lot of them in our favour'.
"We've got to learn from whatever we've got to do, whether it's skill-wise, strategy-wise, mental-wise, to get through that 20-minute patch when things aren't going for us."
With five wins, six losses and a position outside the top eight, Voss conceded every game for the Lions was now "super crucial".
Ash McGrath looks set for a stint on the sidelines after sustaining a hamstring injury Voss believes will keep him out for more than six weeks.
