Asked if his side threw the game away, Mel said: "Yes, of course.
"The start of the game was good for us. It is incredible to score three goals away and get no points."
West Brom did piece together some good attacks and dominated possession in the second half but they were undone by some poor defending.
Mel, still awaiting his first win, said: "I think we need to improve on mistakes. For example the first goal was a mistake.
"But I believe our problem in this game was Benteke and not so much our defence.
"We worked all week on the direct play of Aston Villa and I think this was our problem."
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