An Ivan Toney double saw the Bees win 2-0.
Tarkowski said, "We had chances, they had a couple. They got the goal at the end late on so disappointing but no time to panic. It wasn't a bad performance but not our greatest.
"We can't let any player break into the box like that especially someone of [Christian Eriksen's] quality. We've given away too many cheap goals like that this season which needs to stop. We need to be better once again in both boxes. We have a lot more than that.
"A lot of the time if someone goes down in the box with the slightest of touches it gets given.
"There are plenty of teams who have to pick up points but we'll just concentrate on ourselves. No time to panic. Plenty of games left. We need to start putting more points on the board."