Reading twice went in front, only for West Brom to equalise each time. Both sides finished with ten men.
Reading made the perfect start with the fastest goal in the club's history.
From the kick-off, West Brom's Graham Dorrans passed back to Gianni Zuiverloon. He lost possession to Reading's Jimmy Kebe, who then sprinted forward to score from an acute angle on the left hand side of the area.
The goal was officially timed at 9.5 seconds.
Sloppy defending by Reading gifted West Brom their equaliser. Chris Brunt tricked his way past full-back Ryan Bertrand and sent over a left-foot cross that found Robert Koren unmarked at the far post.
It was a simple task for Koren to tap the ball across the line from close range.
Koren was originally due to start the game on the bench but was drafted in at the last minute when Andwele Slory dropped out.
Reading had made the perfect start to the first half but had a disastrous start to the second when Republic of Ireland international striker Shane Long was shown a red card for a tackle on Abdoulaye Meite.
Reading immediately replaced him with Simon Church up front, taking Brian Howard off from midfield.
Just after the hour both sides were down to ten men. West Brom substitute Youssuf Mulumbu had been shown a yellow card with his first touch of the ball after coming on at half time.
He then hauled Brynjar Gunnarsson down and was shown a second yellow by referee Chris Foy.
Eighteen minutes from time Reading were back in front with two substitutes combining to set up their goal.
Gzregorz Rasiak chipped the ball over West Brom's defence for Church to run onto.
The Wales international striker tried to chip keeper Scott Carson, who just got his right hand to the ball. It fell back to Church who calmly stroked it into the net.
West Brom were not finished though. With three minutes on the clock, Joe Mattock overlapped down the left wing, found himself in space and lashed the ball into the far corner of Reading's net.