The Red Devils visit rock-bottom Sunderland. And as an international break follows immediately afterwards, Smalling accepts United cannot falter again.
"After Saturday's defeat, this week was crucial," he said.
"It was two tough away games and we have started pretty positively.
"Now we need to make sure we get three points on Saturday, then things will look a lot better going into the international break.
"If we don't get that win we have two weeks to ponder on what may have been."
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