Germany, who play Kazakhstan on Friday and then again on Tuesday, currently lead the Swedes by three points at the top of Group C, but Erik Hamren's men have a game in hand.
Furthermore, following a 4-4 draw in Berlin, they enjoy home advantage for the final group game between the two nations on October 15, a game which could determine who will book a ticket for Brazil automatically and who would have to go into a play-off.
"We can't prevent that by ourselves," said Lahm. "If Sweden win all of their games, then that's how the situation would be.
"But I wouldn't be afraid. Knockout games are always interesting and I see that as a challenge, but we don't need to concern ourselves with Sweden just now.
"We have a few other challenges to overcome and we shouldn't place the second step before the first.
"We are just looking at ourselves and if we perform, then I'm sure our quality will see us through."
Lahm's optimism does not end at simply qualifying for the World Cup, however, as he has his sights on winning the trophy next year.
Germany have reached the last four of every major tournament since 2006, losing in the final of Euro 2008 and stumbling at the semi-final stage of the last two World Cups, as well as at Euro 2012.
"Given our history and the quality of our current squad, we cannot go to a major tournament without the ambition of winning it," he told the German Football Association's (DFB) website.
"As a professional sportsman, you are always ambitious, you want to win as many titles as possible.
"Of course I have the dream of winning the World Cup, but we have to focus on our current goals and once we have done that, our aim has got to be to prepare as well as we can for the World Cup.
"The next aim has got to be to get through the group stage. Step-by-step, a dream can be the result of many aims, which is why the next aim is always the most important one."