It was a tremendous effort from The Reds as they twice came from behind to draw in a game which referee Keith Stroud made a string of errors which looked set to cost Forest at least a point.
Callum Robinson put the hosts ahead before Kyle Bartley’s own goal levelled the scores. Tobias Figueiredo also put through his own net in controversial circumstances before Cash’s stunning strike saw a share of the spoils.
Sabri Lamouchi made five changes to the side which lost to Charlton in midweek, with Lewis Grabban, Samba Sow and Sammy Ameobi all overcoming injury concerns to start, with Matty Cash and Yuri Ribeiro restored to their full-back roles.
It was a nervy opening few minutes for Forest as West Brom looked to make a quick start, applying pressure on Brice Samba’s goal from kick-off as a couple of loose balls in the box fell kindly for the Reds’ defence who were able to clear.
But they soon settled into the game and a golden chance arrived on seven minutes and one that Grabban would expect to convert. Superb work by Ribeiro on the left saw him cross perfectly for the Forest top scorer, who headed wide of the target from six yards out.
It was an even and well-fought contest, with both sides showing quality and plenty of determination as they went in search of the vital three points. Callum Robinson dragged an effort wide on 13 before some superb skill from Joe Lolley set up a shooting chance on 24 but his right-footed effort was off target.
The opening goal came on 37 minutes as a mistake by Samba Sow allowed Matheus Pereira to steal the ball 30 yards from goal and play in Robinson who calmly slotted home to give Brice Samba no chance.
Forest showed a good response to going behind, with Tiago Silva flashing a volley over the bar on 42 and they were level on the stroke of half-time thanks to a Kyle Bartley own goal.
The error was forced thanks to a superb delivery from Sammy Ameobi, with the winger’s teasing cross into the corridor in front of Sam Johnstone’s goal leaving Bartley with no choice but to try and stop the ball or allowing the lurking Grabban to convert behind him.
The second half started with the home side on the front foot, with Samba called into action to deny Filip Krovinovic and Jake Livermore, before Pereira saw a shot blocked on the line and Samba kept out a stinging volley from Livermore.
Just after the hour mark, referee Keith Stroud took centre stage as a raft of decisions went against Forest to give West Brom the upper hand.
Stroud failed to give a clear-cut foul on Sammy Ameobi deep in the West Brom half on 65, allowing The Baggies to attack with Ameobi stricken on the floor. The move saw Krovinovic drill the ball across goal with Tobias Figueiredo only able to steer the ball into his own net.
He then failed to see two blatant offences against Joe Lolley, firstly as he was taken out right on the edge of the penalty area, then a handball against Kyle Bartley wasn’t seen as Lolley raced into the area.
But Forest kept plugging away despite their obvious disadvantage, Brice Samba on top form to keep out efforts from Robinson and Romaine Sawyers before late drama saw The Reds take a point.
Matty Cash popped up with a stunning effort in injury time, firing high into the top corner to send the fantastic travelling support wild.
A battling performance against the league leaders and a point to show for their efforts as Forest move on to the next challenge against QPR on Saturday.
Forest: Samba; Cash, Worrall, Figueiredo, Ribeiro; Watson (c), Sow (Diakhaby 70’); Lolley, Silva (Walker 80’), Ameobi (Semedo 70’); Grabban
Unused subs: Muric, Jenkinson, Dawson, Yates
Goals: Bartley own goal 45’, Cash 90’
Bookings: Cash 27’, Sow 40’, Samba 71’
West Bromwich Albion: Johnstone; O'Shea, Bartley, Ajayi, Townsend; Livermore (c), Sawyers, Pereira (Phillips 72’), Krovinovic; Robinson, Robson-Kanu (Grosicki 84’)
Unused subs: Bond, Hegazi, Furlong, Harper, Austin
Goals: Robinson 37’, Figueiredo own goal 65’
Booking: Phillips 75’
Referee: Keith Stroud
Attendance: 25,117 (1,977 away)