The Tykes were given a footballing lesson at the Etihad Stadium as a Carlos Tevez hat-trick and further goals from Aleksandar Kolarov and David Silva sent the npower Championship relegation battlers packing in a 5-0 defeat.
Flitcroft's side dropped to the foot of the table on Saturday as relegation rivals Peterborough and Bristol City both picked up points, and the Tykes now have 11 games left to escape the drop.
"We've got a lot of improvement to do," Flitcroft said after his side's City humbling.
"We've got to get back to work in the Championship and then we'll assess things then. It's unfair to assess them against Premier League players.
"Tuesday night is a massive game, but I'm glad it's coming because I wouldn't like a full week to reflect on what I've witnessed.
"At half-time we started thinking about the Brighton game and the significance of that game.
"The fans have been incredible since I took this job. I'm hoping next week we can regroup as a town, as a club and as a group of players.
"We need to kick-start and really get going now because the hullabaloo of the FA Cup is over and we can focus on the league now."