Group C leaders Denmark, with 11 points, lead Scotland by a single point after five matches ahead of the decisive match in Glasgow.
The Danes were held to a shock 2-2 draw by Belarus on Saturday as Scotland lost 3-2 in Greece, meaning Clarke's men can still finish top of the group and seal a place at the World Cup for the first time since 1998.
But a draw would be enough for the Danes, who have a superior goal difference, to qualify automatically for next year's tournament in Canada, Mexico and the United States.
The team that finish second in Group C will be involved in play-offs.
"We always thought when the draw was made that if we could get it down to the final game here at Hampden that would be an achievement because we would then have had to finish above our seeding," Clarke told reporters on Monday.
"We've done that. We were drawn as a pot-three team. We're already in second place. We want to go one step further and finish at the top of the group."
Clarke, who has taken 38th-ranked Scotland to the past two European Championships, was asked whether his players had the chance to become "legends".
"If you look at what we've achieved over the last six-and-a-half years, a lot of these players are already, I'll use your words, 'legends', but they're already very, very high in the ranking of what we've done as a country," he said.
He said some people had warned him that the job would be a "poisoned chalice".
"I looked at the group of players and I said, 'I see some quality there, I see a group of players - I look forward to working with this group of players because I think we can achieve good things'," he said.
"We've managed to do that. Now we've got another very, very good thing that we can achieve together."
Clarke confirmed that Napoli midfielder Billy Gilmour would miss the Denmark game after also being absent for the defeat in Greece with a reported groin injury.