The defender played in the Hammers side that surrendered a half-time lead in their defeat to Liverpool, for whom West Ham old boys, Glen Johnson, Joe Cole scored before James Collins put through his own net.
The east London outfit now visit the Hawthorns, hoping to pile more misery on West Brom, who are on a run of three straight defeats.
“Our aim now is to get back on track against West Bromwich Albion”, O’Brien told Sky Sports News.
“We want to take the points but it is a hard place to go and they have a good home record.
“Hopefully we can get a result but, as you saw against Liverpool, the top teams can produce little bits of magic and you are suddenly behind.
“I thought we played some decent stuff and created some good chances particularly in the first half down the right with Matt Jarvis. We looked good and that is what is disappointing because Liverpool did not play us off the park.”
West Ham will be without influential midfielder Mohamed Diame, who suffered a hamstring injury in Sunday’s defeat. The Senegalese joined Andy Carroll, Ricardo Vaz Te and Yossi Benayoun in the treatment room.
Midfield duo Jack Collison and Alou Diarra are on course to return from a long-term knee problem and thigh strain respectively, but are unlikely to recover in time for the West Brom fixture.