By Jack Cook
The Bluebirds chief insists valuable lessons were learnt that day at Loftus Road as some strong words were exchanged in the dressing room.
City recovered from that defeat to go on and reach the play-offs and return to London on Saturday on the back of a five-match unbeaten streak albeit while still waiting to ignite their Championship challenge.
“You can laugh about it now, but some very valuable lessons were learnt that day for me as a manager,” said Harris.
“It was one of those moments that was hard-hitting, there were some defining moments in the changing room that day. Some strong words were said.
“A lot changed afterwards over a period of time. I certainly expect a different outcome tomorrow.”
Cardiff are 14th in the table having draw their last three games, coming back from conceding the first goal each time.
QPR are 19th with their only win coming on the opening day against Nottingham Forest.
City have not won at QPR since 2010 with Harris looking to get avoid another draw as they look to move up the table.
“Clean sheets and score more goals,” said Harris, of what is needed from his players.
“It was put to me the other day, searching, stuttering start. That’s what we are doing at the moment.
“We are not winning enough to make sure we are affecting those top few positions.
“Consistency in team selection would be nice but with the amount of games we have got we can’t use the same team continuously.
“But it’s about taking our chances and having our best players on the pitch.”
Star signing Harry Wilson is unlikely to be on the pitch on Saturday after picking up a hip injury that forced him to miss Wednesday’s draw at Derby.
But Harris is hopeful the Wales international will be back next week if he is ruled out of the QPR trip.
“Positive developments,” said Harris of his loan signing from Liverpool. “No muscle injury, just a hip infringement.
“It’s just probably come through the big spike in minutes after him playing in three games in that first week, continuously striking the ball with his left foot.
“Whether tomorrow’s game comes too soon, we’ll have to see on the training pitch. If not we’re certainly hopeful for next week for the home games.”
But Lee Tomlin is due to make his return after not featuring since his sending off against Blackburn.
Harris added: “Good week for Lee he’s been on the training pitch so we are hoping that he can travel with us to QPR.
“We miss him in the group, we miss his liveliness and chirpiness. He’s an important member of the group and the most important thing is that we miss him on the football pitch.
“Those little moments in games, those fine margins, players of Lee’s ability he can change those fine margins.”
Fans have been calling out for winger Josh Murphy to be given his chance after his impressive end to last season with the winger yet to make his mark this season.
“Murph played 60 minutes against Middlesbrough and I was pleased with his performance,” added Harris. “I think with players and the manager things happen for a reason on the pitch.
“Murph was about to come on (against Derby), we scored the goal so I changed my mind on the substitution.
“I fancied us to go on and get another goal with the team we had on the pitch and you go on that gut feeling.
“He’s training everyday so he is currently fitter than he was a couple of weeks ago.
“Sometimes as a manager you want to see players every day at the top of their game, busting a gut to be in the team and to show me every day that they should be in the team.”