On loan winger Wayne Routledge had put Cardiff in front in the 10th minute when he did the defence for pace.
It was Reading's turn 6 mins later to show a clean pair of heels. Cardiff took a corner, one touch cleared it down the line to Jimmy Kebe who beat Miguel Comminges for pace to get to the bye line and square for Kevin Doyle to score.
Reading's luck changed when Bikey was given a straight red for raised hands against Michael Chopra on the half hour. And just 10 mins or so later Chopra was scampering around the ankles of Marcus Hahnemann and the big American bundled Chopra to the ground and Cardiff were awarded a penalty.
Ross McCormack scored and left Reading staring at a second half a man down and a goal down.
But a sweet passing move saw Gunnarsson score 5 mins after the break.
Fr the remainder of the game Reading absorbed pressure and looked to attack on the break. The comfort in which the Royals kept Cardiff out will please Steve Coppell when defet at one stage looked the only outcome.
Next up Reading face Coventry on Monday evening.