Cardiff manager Dave Jones admits he is still hurting from last year's play-off final defeat to Blackpool at Wembley.
But he says his players have already proved their character as the Bluebirds bid to go one better 12 months on.
Cardiff travel to the Madejski Stadium on Friday night for the first leg of their semi-final, before welcoming the Royals to the Welsh capital on Tuesday.
"I'm still smarting and hurting from last year and that's why we've worked so hard to get back," Jones said.
Nine of the 18 players involved in the Bluebirds' 1-1 draw at Burnley on the last day of the regular season were not involved in last year's 3-2 defeat to Blackpool.
But Jones believes the pain of that Wembley defeat, and the lost chance to play in the Premier League, should be a lesson to every Cardiff player.
"I hope they're hurting. That's what I do hope," Jones said. "It still hurts me, it still sticks with me. Like most games I've lost.
"The bigger the prize, cup finals and games like that, they're the ones that stick with you. They're the ones that hurt the most.
"You can get over a league game because you get another opportunity to try and correct it.
"But at this stage, when you get to the end of a long haul, they're the ones that hurt you the most because they're the ones that stick in everybody's mind.
"A lot of people said you can't pick these players up and go again, and we have.
"I think we're the only club to have been beaten in the final and gone back the following year into the play-offs. So that's an achievement in itself."
Jones says that despite missing out on automatic promotion from the Championship, falling away at the death to allow Norwich to take second spot behind Queen's Park Rangers, the mood within his squad is upbeat.
"Listening to some people, the spirit in the camp is not meant to be very good," Jones said.
"I haven't seen that, it's very buoyant, we've got over the disappointment of not going up automatically.
"The disappointment on Saturday from some people I spoke to was just over the top, we've just achieved another fantastic thing by getting into the play-offs. I think people forget that.
"Over the course of the season we've come a long, long way, even from last year.
"We seem to have this divine right to get automatic promotion - maybe we should have done, maybe we shouldn't, but we didn't. We've still had a fantastic achievement.
"We're one of four clubs in this division who have never been in the Premier League, yet we're knocking on the door again."
Cardiff goalkeeper Tom Heaton (groin) will have a late fitness test ahead of the first leg against Reading.