Northern Serbia hosts the Hammers for a Group A fixture which could see them qualify for the knockouts with a game to spare.
Olympiacos sit five points behind West Ham with only six left to play for and the Greek giants take on Freiburg, who are set to be their rivals for top spot.
Backa Topola look destined to be dumped out of Europe at the group stage but did worry the east Londoners by taking the lead in the reverse fixture at the London Stadium.
Mohammed Kudus eventually led West Ham to a convincing win on that occasion and another victory is required from them tonight.
Where to watch Backa Topola vs West Ham
TV channel: In the UK, tonight's game will be televised live on TNT Sports 1, with coverage beginning at 5pm GMT ahead of a 5:45pm kick-off.
Live stream: Subscribers can also catch the contest live online via the Discovery+ app and website.