All the best match action from Tuesday night's gameAll the action from Tuesday night's encounter is included here in our special photo gallery.
With Ian Holloway's side pressing for a third, winning, goal it was The Royals who shattered Millwall's hopes of picking up all three points with a late close-range effort from Cox to seal a victory that was so harsh on Millwall.
But the battling Lions refused to give up and turned the game on its head to draw level with goals from Ricardo Fuller (39mins) and Mark Beevers (53mins).
Nigel Adkins side roared into a 2-0 lead in the opening 14 minutes with goals from Simon Cox (6mins) and a Nick Blackman penalty after Byron Webster was penalised for a foul.
Millwall were left wondering what might have been after Reading snatched a dramatic last-gasp winner in a pulsating clash at the Madejski Stadium.