A late Ipswich Town winner from Freddie Sears ensured that Nottingham Forest left Portman Road empty handed after Christophe Berra's calamitous own goal looked to have cancelled out Daryl Murphy's 25th goal of the season.
Murphy was similarly careless with his first effort of the afternoon, nodding Teddy Bishop's corner over the bar when well placed.
However, the Championship's top scorer made no mistake with his next opportunity, collecting Sears's pass and hammering the ball beyond Karl Darlow from inside the area.
Forest levelled the tie in fortuitous circumstances just eight minutes after the restart as Berra stumbled in the box and turned Ben Osborn's cross into his own net.
Substitute Luke Varney then twice tested Darlow with headers in the space of a just a few minutes as the home side made all the late running.
Just as Forest looked as though they would escape with a draw, Sears cut inside Jack Hobbs and hit a strike that deflected up and into the back of the net.