After Marco Reus cancelled out Ola Toivonen's opener, Kroos scored the winning goal in second-half stoppage time, whipping a scintillating free-kick into the top corner from an acute angle.
The result ensured Germany go into their final Group F match against South Korea knowing a win will put them into the tournament's knockout phase – a fate that seemed unlikely at times against Sweden.
Although he recovered in spectacular fashion late on, Kroos was guilty of giving the ball away lightly in the build-up to Toivonen's well-taken goal and the Real Madrid star held his hand up to the error.
"All in all we did not capitalise on the stages in the game in which we were really good," Kroos told ARD.
"If you play 400 passes in the game, two will not come good. If one of them leads to a goal, that's stupid.
"But then you have to have the balls to play the second half like that, but only a few can do that."
Germany's performance was an improvement on their World Cup opener, which they lost 1-0 to Mexico.
Against Sweden, Joachim Low's men attacked fluently throughout and cut out their occasional defensive lapses in the second half to see out the win.
"We have been much criticised, rightly at times," said Kroos.
"One had the feeling that a relatively large number of people in Germany would have been happy if we had gone out, but it's not that easy."