A Chris Gunter own goal put Brighton in front in the 16th minute on Saturday but Gordon Greer was shown a second yellow card just five minutes into the second half, with Royston Drenthe going on to equalise for the Royals in the 64th minute.
Reading came close to breaking the deadlock in only the second minute when Drenthe beat three men before crossing perfectly for Adam Le Fondre, whose goal-bound shot was blocked by defender Stephen Ward.
Brighton goalkeeper Tomasz Kuszczak then rose to confidently claim a dangerous ball in by Hal Robson-Kanu under pressure from Le Fondre.
The Seagulls gave a home debut to striker Jesse Lingard, on loan from Manchester United, and when he was brought down 25 yards from goal Jake Forster-Caskey had a free kick blocked.
Reading fell behind in unfortunate circumstances after 17 minutes when, following a cross into the box by Spaniard David Lopez, defender Gunter headed into his own net with goalkeeper Alex McCarthy helpless.
The Royals threatened when Jordan Obita crossed dangerously in the 26th minute and former Crawley midfielder Hope Akpan drove narrowly over from the edge of the area.
Greer received his first booking for bringing down the on-rushing Le Fondre and, after play broke to the other end following a run by Lingard, Forster-Caskey was off target from the edge of the box.
Lopez failed to make the most of an opening for Brighton just before the break when he put a right-foot shot wide from 20 yards after a free kick from Forster-Caskey was worked to him.
Robson-Kanu made his presence felt straight after the interval with an excellent cross which just eluded Le Fondre.
The Seagulls were reduced to 10 men in the 51st minute when centre-back Greer collected his second yellow card for a late challenge on Le Fondre, and head coach Oscar Garcia introduced substitute Lewis Dunk in place of Lopez.
Brighton were relieved to see a close-range header from Le Fondre go over the bar following a cross by captain Danny Guthrie, before Nick Blackman drove narrowly wide from 20 yards.
Former Real Madrid midfielder Drenthe pulled Reading level on 64 minutes by beating keeper Kuszczak at his near post with a low shot from just inside the area.
Reading should have extended their advantage through Blackman who shot straight at Kuszczak before Will Buckley put a good chance wide for Brighton after being set up by Leonardo Ulloa.
Kuszczak came to Brighton's rescue with a superb save to deny on-rushing substitute Jobi McAnuff 10 minutes from time.
Buckley then forced keeper McCarthy to make a vital save in stoppage time as both sides pressed for a winner.