Clarke said: “Two away games, you’re probably looking at them and thinking that four points would be the minimum that we’d want to take for the games – we managed to get the four points.
“It gives us a good platform going into two home games and obviously the two home games are important as well.
“But then you go to November, there’s two more games and they’re going to be important. So the whole process is truncated in a short period of time, but we understand what we have to do.”
There is no room in Clarke’s squad for in-form Hearts striker Lawrence Shankland, or Oli Burke, who netted a hat-trick for Union Berlin against Eintrecht Frankfurt in the Bundesliga earlier this month.
Clarke said he monitored both players’ recent form but preferred to go with the players who helped Scotland perform well in the opening two matches of the group.
“I think about all these players,” he said. “Because I tend to pick the same players more often than not, people think that I don’t look outside, I don’t look at other options.
“I’m always looking at other options because you never know when you’re going to get injuries, suspensions and when you’re going to have to call people into your squad.
“I just felt that the players I had in the last camp did well in the camp, did well in the games and they’ve done well for their clubs in between, so I didn’t see too much reason to change.”
Greece, who beat Belarus then lost to Denmark in Athens, have good memories of their last trip to Hampden.
Trailing 1-0 from the first leg of a Nations League play-off in March, the visitors ran out comfortable 3-0 winners in what was Gordon’s most recent international appearance.
With Clarke opting for a smaller squad, there is no room for Shankland, Burke or Middlesbrough forward Tommy Conway.
Anthony Ralston, who withdrew from the previous squad along with fellow Celtic full-back Kieran Tierney, returns after making his club return at the weekend after a month out.