"It was shocking defending today on two occasions, which stopped us winning the game," said Allardyce. "Just two sloppy pieces of defending has gifted the opposition two goals and made life very difficult for us on what was a very accomplished performance other than that."
The result keeps United in the playoff places, but Allardyce revealed that they were behind a points target that he had set for them.
"We have 18 points from the first phase, the first ten matches. It is two points behind what we wanted but I expect we will make that up if we continue to grow as we showed today."
West Ham next host Blackpool in the Championship in two weeks.