Flitcroft has steered the Tykes to eight wins, two draws and three defeats since taking over from predecessor Keith Hill at the end of December, including FA Cup victories over Burnley, Hull and MK Dons.
"If we get the level of performance that I expect then it will enhance it and we can keep building," Flitcroft said ahead of Saturday's quarter-final clash at Manchester City.
"What we've been doing, each game, whether we've won, drawn or lost, we've taken the positives out of that performance and if we get a positive performance on Saturday we'll take that into Tuesday night's game against Brighton.
"The league campaign is our bread and butter. It's something we've really committed to and dedicated to and we won't swerve from that.
"But as a manager I've got a capacity to switch on and off, focus and refocus and that's really important. I can regroup my players and get us switched on from FA Cup to league and we've shown we can do that.
"We beat MK Dons after a real tough encounter (at Middlesbrough) and then Wolves came to us in a desperate fight and we beat them 2-1, so it's not hindered our league form up until now.
"The only thing that's causing a concern is a pile-up of games really. We've got a game in hand now on Wolves, but you'd rather have three points in the bag."