Nottingham Forest will be ruing their slow start after Reading scored twice in the first 13 minutes to establish a 2-1 half-time lead at the City Ground.
Pavel Pogrebnyak and Kasper Gorkss both netted within the space of five minutes as the Royals came flying out of the blocks, before Simon Cox pulled one back for the hosts before the interval.
Former Forest winger Garath McCleary, playing against his old side for the first time since leaving them for Reading, fashioned the visitors' opener with an adventurous run on the right wing.
He drove into the area, taking on two Reds players in the process, before fizzing a cross towards the back post, where Pogrebnyak was on hand to tap in his fifth Championship goal of the season on eight minutes.
Reading's advantage was doubled five minutes later, when Danny Guthrie's pacey corner was headed in by Gorkss, who stooped low to guide the delivery into the roof of the net.
Forest recovered from a disastrous first half-an-hour as Henri Lansbury came close to a reply with a pair of curling efforts which went narrowly wide, but Cox did find the target to reduce the deficit.
Jamie Mackie raced onto a header over the top from Gonzalo Jara, and squared for his strike partner Cox, also playing against his former club, to convert into an empty net from close range.