Steve Clarke says no one should doubt his Scotland players despite a blistering run of form that has stretched more than a year without a competitive win.

Saturday’s 2-1 Nations League defeat to Croatia in Zagreb means the Scots have won just one of their last 15 games – a friendly against Gibraltar.

As his side prepare to face Portugal at Hampden on Tuesday, the head coach insists he continues to believe in his players.

“It’s a tough moment, no doubt, but we believe in ourselves,” Clarke said.

“After 20 years in the international wilderness, this group has played in two major tournaments and been promoted to the highest level of the Nations League, so I don’t see why there should be any doubt.”

“We have to believe in what we are doing and when I look at the players on the pitch, I believe in what we are doing.”

“The players understand where we are in the process and they are ready to get going again.”

“They understand that we are playing against difficult opponents and they understand that the team could be stronger.”

“I don’t talk about that too much because we have to focus on who we have here. We have to go against Portugal knowing that we have to be good at everything we do in the game.”

Scotland have lost each of their three Nations League A games by a single goal, Poland at Hampden, away to Portugal and at Croatia at the weekend.

Clarke says his side will have to “find another level” if they are to beat Portugal’s superstars and is sure they can draw confidence from their performance in Lisbon last month, when Cristiano Ronaldo’s late goal denied them a point.