Robertson copped criticism for his performance in the 1-1 draw with Israel on Sunday.
Some have accused the 27-year-old of failing to replicate his Liverpool form at international level, but Clarke disagree.
He said: "It's a problem more for the media, the pundits and the supporters. Not for us.
"I thought our left hand side, with Robertson and Tierney - whether Kieran was at left centre-back and Andy at left-back or Kieran left of a three with Andy left wing-back - worked well.
Asked if Robertson struggles to replicate his club form at international level Clarke responded: "I think it's unfair, it's a different team.
"Listen, we've spoken about this one before with everyone saying you can't get Kieran and Andy in the same team. But we can do it. We've done it. Consistently.
"And maybe that's one of the reasons we've qualified for a major tournament. Both of them were decent that night. For me it's no longer a discussion. We can do it.
"They can play in the same team. Kieran likes to play on the left as well as Andy. I think we have found a way to do that."