West Ham sealed a place in the last 16 of the Europa Conference League after defeating Silkeborg to maintain their 100% winning record in Europe this season.
Manuel Lanzini's penalty, after Michail Antonio was brought down by keeper Nicolai Larsen, ensured the Hammers qualified with one game to spare.
Last season's Europa League semi-finalists dominated with Algeria winger Said Benrahma and Spain midfielder Pablo Fornals both going close to extending the lead against the Danish visitors.
West Ham keeper Alphonse Areola was forced into a fine save to keep out Soren Tengstedt in the second half.
With one round of games to go, David Moyes' side cannot be caught at the top of Group B.
They have 15 points from five games, nine more than second-placed Silkeborg.