Norwich were thrashed 7-0 on Saturday.
Scotland international Martin, 27, said: "I just don't know where that performance has come from, because even though we haven't been picking up results lately we've been playing okay in bits and bobs.
"The whole team just weren't good enough from start to finish.
"We had a little bit of misfortune with the first two goals but after that we totally capitulated and that's not like us."
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