The Tykes, hammered 6-0 by Charlton on Saturday, bounced back with a 1-1 draw against Derby.
Chris O'Grady put them ahead and they were only denied a victory which would have lifted them out of the drop zone by a last-gasp John Brayford strike.
"The players are feeling the pressure of the situation, there's no doubt about it," said Flitcroft.
"Don't forget we got downed 6-0 at home and we've had two players sent off. That's still in the back of the players' minds.
"They didn't want to get smashed again. It was a brave performance but we didn't get the result we wanted.
"It's not a difficult one to take, it's just disappointment. It's an emotion we're going to have to soon get over.
"We did enough to win that game but we're not going to be victims, we'll keep fighting until the end.
"We'll grow stronger over the next few games because we'll get players back from injury and suspension.
"I asked the players to raise their game 20 per cent in the second half, because that 20 per cent would have been enough to beat a really nervy Derby team.
"It wasn't the right result but I got the performance from the players that I was expecting."