The Reds took the lead after two minutes against Tony Pulis's side on Wednesday night; however, Jonathan Walters equalised before Kenwyne Jones added a second and Walters made it 3-1.
"I said during the week and last week that [consistency] will be the biggest thing for the group," explained the manager during his post-match press conference.
"We were terrific at the weekend [against Fulham] but you have got to be able to put a run of games together - if not you just keep taking two or three steps forward and making one or two back and then going again.
"That's been the nature of the group over the last couple of years in terms of where we have finished. We're looking to improve that. There is still an awful lot of work to do.
"We conceded soft goals tonight after a great start. A terrific ball by Martin Skrtel and a bit of magic by Luis for our first pen of the season and Steven sticks it away perfectly. We are one-up in a difficult place to score goals.
"The first goal [we conceded] we were rather unfortunate - Skrtel slips and then Walters finishes really well. But the other two goals, we have to be better than that. The players have to be better in those moments.
"You have to earn the right to play in whatever game - and in particular when you come to here. You know you are going to get pressed. I have no doubt about the characters we have - we have some big characters and big players, but tonight it was just too easy for them."