Edson Alvarez was sent off for West Ham as Julen Lopetugui’s side fell to a dismal 3-0 defeat at Nottingham Forest.
Goals from Chris Wood, Callum Hudson-Odoi and Ola Aina saw off a ragged Hammers team to take Forest third in the Premier League.
Not since August 1998, when a 2-1 win over Southampton left Dave Bassett's side second in the standings, have Forest sat so high.
They ended up being relegated that season but their ambitions are much loftier this time around as they appear to be building something special under Nuno Espirito Santo.
This was their third win in a row and in a season of strange results, they could mount an unlikely top-six challenge.
That already looks impossible for West Ham, who were unable to build on last week's win over Manchester United, and boss Lopetugui will be under some scrutiny after a less than impressive start to his reign.
They were never in this one as Forest dominated from the first whistle and forged an early opening when Aina and Anthony Elanga combined down the right. The latter teed up Hudson-Odoi but the winger could not get his shot on target.
The hosts continued to dominate and were rewarded with the opener in the 27th minute as Wood continued his hot streak.
Morgan Gibbs-White, back in the side after injury, set Alex Moreno free on the left and the full-back's dinked cross was nodded home by Wood from six yards.
It was Wood's 23rd Premier League goal for Forest, which moved him clear of Stan Collymore and just one behind leader Bryan Roy in their all-time list.
The New Zealander proved himself just as important at the other end of the pitch in the first minute of first-half injury time as he protected the lead he had given his side by producing an impressive goalline clearance to deny Lucas Paqueta.
Less than 60 seconds later, West Ham's plight worsened when Alvarez picked up a second yellow card after a reckless tackle on Elanga.
To make matters worse he had to endure an extended walk of shame as he forgot where the tunnel was and mistakenly walked down to the corner flag.
The Hammers, who almost conceded a second just before the half-time whistle when Nicolas Dominguez poked over, made changes at the break as Michail Antonio came on to provide some presence up top.
But it did not make any difference as Forest dominated against the 10 men.
Hudson-Odoi had already fired a warning when bending a trademark effort just wide by the time he doubled the lead in the 65th minute.
Elliot Anderson picked out the former Chelsea man on the corner of the area with a quick free-kick and his curled effort made it through a crowd of bodies and sneaked in at the far post.
It was one-way traffic and Nikola Milenkovic sent a header just wide before Aina made it three in style with 12 minutes left.
The full-back ran across the face of goal and then fired an unstoppable drive into the top corner.
It could have been even more emphatic as Lukasz Fabianski produced a fine save to deny Milenkovic and Ryan Yates had a goal disallowed for offside in injury time.
