Leeds beat Portsmouth 1-0 at Elland Road, keeping a first Championship clean sheet of the season and extending their unbeaten sequence in the league to four games.
"One or two of them were on their last warnings after last week," he said of his players.
"I criticised the back four and I don't normally do that, but I felt it was time that people took responsibility for what's happened and they responded in the right manner.
"It was a good performance from us, I'm delighted that we kept a clean sheet for the first time this season.
"The players have taken on board what we have worked on this week.
"When they were called on the defenders defended and the goalkeeper made some good saves. We're trying to get the right balance between attacking and defending and we're delighted to keep the clean sheet.
"You have to be able to see stages of a game through and be determined and professional. We've probably been a bit naive, going gung-ho for the next goal, but we needed to be professional and we were."
Portsmouth boss Steve Cotterill felt his side showed signs having played three games in eight days.
"In the second half, we were much improved," he said.
"In the first half we looked like it was our third game in eight days and they looked fresher than us for not playing in midweek.
"But the way we played in the second half makes it harder to understand why we were so lethargic in the first.
"It was the first goal we've conceded from a set-piece, and if someone loses their man there is not a lot you can do."