- Tomás Soucek (89')
Soucek struck one minute from time, evading his marker and volleying home a cross with his outstretched right leg.
Defences dominated a dull game and the hosts had the better opportunities to break the deadlock until the final stages.
West Ham top the standings with 12 points, level with German side Freiburg who the English team host in the final round of matches on Dec. 14.
Michael Gregoritsch's hat-trick earned Freiburg a top-two spot as they thrashed visiting Olympiakos 5-0.
West Ham will only need a point against Freiburg to secure top spot and avoid a playoff in February against a team that finished third in their Champions League group in order to make the round of 16.
Reuters contributed to this report.
- Allard Lindhout