Liverpool moved 19 points clear at the top of the Premier League after beating under pressure West Ham 2-0.
David Moyes’ side had started the game in strong form, limiting Liverpool’s scoring chances.
But Issa Diop’s foul on Divock Origi handed the Reds a loophole and Mohamed Salah scored a 35th minute penalty to put his side forward.
The Hammers did have chances to score in the second period, notably via Manuel Lanzini’s scuffed close-range shot and Robert Snodgrass’ hurried effort.
Then Oxlade-Chamberlain scored the second goal from a right-foot shot into the bottom left corner after good work from Jordan Henderson and Salah at the 52nd minute.
Jurgen Klopp’s side, who are now unbeaten in 41 Premier League remain top of premier league while West Ham are 17th, above 18th-placed Bournemouth, and Watford in 19th, on goal difference.