Response key for Royals bossManager Steve Clarke spoke about his players in glowing terms after a 2-1 comeback win in the FA Cup.
The Royals are just two wins away from Wembley after victory in south Wales, Oliver Norwood and Hal Robson-Kanu the scorers in the second half.
The second half was very pleasing for the manager, who praised a change in mentality after the opening 45 minutes.
Clarke told Reading FC Player, "We kept driving on and deserved to go through.
"Hopefully the supporters, who made a lot of noise, just like they did at Fulham, will go home happy.
"I was delighted with the team in the second half. Being honest I was disappointed first half, we coasted along, Cardiff punished us from a set play and there was no real reaction, the only reaction was from our supporters.
"But we had a chat at half time, made a slight change to the system, nothing you would notice but it was quite effective. The biggest change though was the attitude, the mentality, and second half was the Reading team I want to see going forward.
"I'll watch the video to see to what extent the change was something tactical, but my gut feeling is that it was predominantly a change in mentality. We were more aggressive, on the front foot and by the far the better team second half."
The boss highlighted a number of players for their performance, saying, "Pavel had a lonely shift, he never stopped, I thought Blackman was excellent, drove us on, and we know Olly has got excellent delivery from free kicks. He second-guessed the keeper and it shows the value of having good delivery.
"I was absolutely delighted for Hal, he came off the bench and did what I ask of all my subs, to have an impact. It's great to see, especially here in Cardiff which I'm sure he enjoyed."
On an afternoon of cup surprises, fans of every club left in the competition will eagerly await Monday night's draw, but the boss cautioned, "Not everyone has gone out! You just have to see who you get and try to progress.
"More important for us is Tuesday night, it's a big game we want three points from and we want to take momentum into it. We want a winning mentality, not rolling over, not dropping silly points, hopefully this is a step."
Lastly the boss confirmed that Chris Gunter is a doubt for the Millwall game, having been withdrawn with an ankle problem, while Danny Guthrie and Jamie Mackie missed out with groin injuries.