The Reds signed Sheffield Wednesday striker Chris O'Grady and Stoke midfielder Rory Delap on loan until the end of the season on transfer deadline day following the arrival earlier in the week of forward Jason Scotland.
Both Delap, who started, and O'Grady made their debuts in the weekend win at Blackpool, while Scotland stepped off the bench to score Barnsley's winner for the second successive match.
"Every man who has played his part has been incredible," said Flitcroft after his side had made it 10 points from four matches with their 2-1 win at Bloomfield Road.
"It's important I make sure no complacency sets in. We've got some quality players on the bench who can give us a lift.
"It gives the lads a lift with the likes of O'Grady and Scotland coming on. It's almost time stands still for Scotland in the box - it's incredible.
"The substitutes in the group are vital. We're not interested in what other teams are doing. It's about what we do."