West Ham United boss Sam Allardyce admits Chelsea went into their shell in the second-half of their derby win.

Allardyce's charges overran Chelsea after halftime.

"You can see the quality they've got but in the second half they didn't quite show as much resilience as they needed to," said Allardyce.

"They couldn't change the way they played to cope with us. We changed the way we played to cope with them and expose them. They couldn't do that against us in the second half."