“Over the three games you’re definitely looking at below-par performances,” said Willie Miller, who played at the 1982 and 1986 World Cups for Scotland.
“I keep looking back on the Denmark game [November’s 4-2 win to seal qualification] with those outstanding goals, but they didn’t get anywhere near those levels.”
The former defender described the lack of a top-class striker as “a major issue” and said he was “uncertain about the logic of a few selections”.
However, he did back Clarke by adding: “He got us there and that’s what the Scotland manager’s job is.
“He has introduced a real togetherness in the squad as well, which wasn’t always the case.”
With 81 matches under his belt, Clarke is Scotland’s longest-serving manager.
Support from the Scottish FA has been emphatic, with their coffers significantly enhanced by participation at three of the past four major finals.
Euro 2028 will be staged in Scotland, England, Wales, and the Republic of Ireland and it will be difficult for the co-hosts not to qualify.
“I’m sure he can go again over the next few years if he wants to,” Miller added of Clarke.
“The new contract was a positive step. I think it was the right thing to do.”
Scotland conceded soft, early goals in defeats by Morocco and Brazil, with former striker James McFadden saying: “The defending was certainly below the standard we’re used to and the errors were costly.
“I just feel the players could have shown more. We could have done better against Morocco in terms of having a go.
“But a lot of people think we should have had two penalties and a red card in that game, which is nothing to do with the manager and players.
“Against Brazil, we gave them two gifts.”
