The Baggies have won back-to-back matches and are five points clear of third place, while Derby have been in good form and are within three points of the playoffs.
The pressure had been building on West Brom after going four games without a win either side of the three-month hiatus, failing to score in any of those matches.
Slaven Bilic called on his players to step up and they have done that in their last two matches, following up a 3-0 win over Sheffield Wednesday with a 4-2 victory over Hull City.
Seven goals scored, six points on the board and now just a few wins away from securing a return to the top flight after a two-year absence - it has been a good week for Bilic.
The job is not complete yet, however, with Brentford winning five matches in a row to keep the gap on Albion to six points with five matches to play.
West Brom still have Fulham to play in the run-in, while this visit of seventh-placed Derby should also be a tricky test.
The Rams had won four in a row prior to Saturday's 1-1 draw with Nottingham Forest, though even that would have felt like a win given the nature of the result.
Cardiff City also scored a late goal later in the day to beat Bristol City 1-0, so Derby have a three-point gap to make up on sixth place.
Philip Cocu's men still have to travel to Cardiff in what is a tough set of fixtures to conclude the campaign, with Brentford, Leeds and of course West Brom also still to come.
It is very much a case of one game at a time for County, starting with this trip to a West Brom side without back-to-back home wins since the start of December.
Derby, by comparison, have won three away games on the spin and will be targeting all three points on Wednesday.
With Cardiff at home to Blackburn on Tuesday, anything less for the Rams could seriously dent their playoff aspirations.
West Brom's Championship form: LDDLWW
Derby's Championship form: LWWWWD
Grady Diangana scored four minutes after being introduced from the bench against Hull at the weekend and may have done enough to win back a place in the starting lineup.
Derby have two players banned for this match, meanwhile, with Tom Lawrence and Waghorn having to watch on from elsewhere.
West Brom possible starting lineup:
Johnstone; O'Shea, Bartley, Ajayi, Townsend; Harper, Sayers; Diangana, Pereira, Grosicki; Austin
Derby possible starting lineup:
Hamer; Bogle, Clarke, Evans, Lowe; Rooney, Bird; Knight, Sibley, Holmes; Martin
We say: West Brom 1-1 Derby
Derby are unbeaten in their last three meetings with West Brom, including a 1-1 draw in the reverse fixture 11 months ago. Both teams enter this game on a high and we can see the points being shared.