The 3,000 travelling fans who had sung and cheered throughout a one-sided game fell silent when the news that Fulham had scored at Portsmouth came through.
There was nothing Reading could do but hope that Portsmouth could reply, but when Mike Riley blew the final whistle, Steve Coppell's team were Championship bound along with Birmingham and Derby.
At least Reading can take consolation in the fact they look far better equipped to come back than Derby, who now share the record with Loughborough Town as the only team in the history of the Football League to win only one game in a season.
Derby were second best by a country mile in this match and could have been four down by half-time if Leroy Lita had not been so lacking in confidence in front of goal.
At the end, the home fans summed it up when they sang "you're not fit to wear the shirt" and "we want our money back" and it is painfully clear that manager Paul Jewell has a huge job ahead of him.
Although Reading were only two places above them in the table, the gulf between the teams was massive and this latest shambolic performance showed why the supporters voted for themselves as Player of the Year.
Marek Matejovsky ran the midfield and created two early chances for Lita that the striker failed to put away.
But a goal was also coming and it arrived in the fifth minute when Dave Kitson broke into the area, played the ball to his right and James Harper curled a left foot shot into the top corner.
Lita missed another good chance before David Jones had Derby's first effort at goal in the 40th minute which Marcus Hahnemann turned away for a corner.
It was his only save of the game as the second half turned into yet another embarrassment for Jewell and his players.
Robbie Savage and Mile Sterjovski were replaced but Derby were no better and Reading increased their lead on the hour when Roy Carroll could only parry a low drive from Nicky Shorey and Lita turned the ball back across for Kitson to score.
Kevin Doyle came off the bench to score the third in the 69th minute following more defensive chaos from Derby and the sea of white and blue shirts in the visiting end celebrated until Fulham condemned their team to relegation.
The players knew from the silence that descended on the fans that Fulham were leading, but Reading ended a two-year stay in the Premier League with another goal when Stephen Hunt crossed from the right and Lita dived full length at the near post to score.
Derby fans spilled onto the pitch at the end and a planned lap of the ground by Jewell and his team was cancelled.
"You're ashamed to show your face," sang the supporters. It was hard to argue with them.