The Reds were slightly fortuitous to defeat Sheffield United, as they nabbed a 1-0 win thanks to a goalkeeping mistake from Dean Henderson.
However, Robertson thinks that it is not possible for the Reds to defeat every side 4-0 or 5-0.
He told the club's official website after the narrow success: "Look, you can't win 4-0, 5-0 every single week by playing beautiful football and everyone claps you off the park because they've been given a show.
"When you're not at your best and the other team are putting you under pressure then it's important to get the win."
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