The world and European champions face Georgia in Albacete in their final clash of the campaign, needing just one point to confirm their automatic place in next summer's tournament.
And Del Bosque has ackowledged that his side's campaign has been tough, singling out their home ties with France and Finland, in which they only managed draws.
"We are hoping to finish first and we have it in our hands," he told reporters.
"We've been through two really bad moments, the game against France at the Vicente Calderon and the one against Finland in Gijon.
"We've had moments of great difficulty for those two results. And yet, people are talking about the World Cup as something we've achieved when we're in a moment of trouble.
"Georgia are not England or Italy, but we have to finish the job. I'm not calm, even though it's true we only have one step left."
Spain's forwards have come under scrutiny over the course of the last year, with la Roja having found the net just 12 times in their seven games, but Del Bosque is convinced of the quality at his disposal.
"It's not right to blame the forwards. [Roberto] Soldado is at Tottenham, Alvaro Negredo is at City, who paid a lot of money for him, [Fernando] Torres has had a great career."
Spain and Georgia kick off at 21:00CET on Tuesday. Second-placed France, who sit three points behind la Roja, host Finland.
