"I was impressed with Forest," confessed Glenn Roeder afterwards. "For the neutral it was exciting to see five goals but luckily we shaded it. Hopefully, this can be the turning point in our disappointing season."
West Ham could not have got off to a worse start though as a dire David James blunder engulfed the Hammers with horror.
This time the confidence drained England keeper let Andrew Reid's tame angled shot leak through his clutches and the busy Marlon Harewood gleefully slid Forest into a 17th minute lead.
Midway though the half, however, Defoe broke the stunned Upton Park silence when he raced onto Joe Cole's pass and clipped a crisp, curling, 15 yarder beyond Darren Ward to level.
That may of been a late let off, but West Ham soon found themselves behind again following the restart when Reid volleyed home Marlon Harewood's deep cross from ten yards.
As Forest went close to putting the tie out of reach, the Eastenders needed a captain's innings and skipper Joe Cole responded on the hour with a low angled 15 yarder to make it 2-2.
But as Harewood and David Johnson continued to cause havoc the Division One side spurned the chance of an instant reply when Christian Dailly illegally thwarted another Forest forward raid.
After dusting himself down, though, Johnson expensively sent his spot kick wide.
It was to prove costly with just seven minutes left destroyer Jermain Defoe chopped down Paul Hart's plucky side as he held off Michael Dawson and Chris Doig before sending Hammers into the next round with a low 15 yarder.
"We did well enough to get something," confirmed Forest boss Paul Hart who saw Johnson's late effort ruled out for pushing.
"I'm very pleased with the performance but disappointed with the result."