Ola Toivenen gave Sweden a first-half lead, but Marco Reus levelled the scores early in the second period before Toni Kroos netted a winner for Germany in the fifth minute of added time at the end of the 90.
Germany have kept their World Cup destiny in their own hands ahead of their final group game with South Korea next week, and Low has insisted that his team "never lost hope".
"Something I did appreciate today was that we didn't lose our nerve, we didn't panic after going a goal down. We kept a level head and said we needed to make quick passes and tire the Swedes out to open up spaces," Low told reporters.
"We didn't score a couple of good chances but we never lost hope we could win the match and I think the goal scored in stoppage time had a bit of luck involved but it did show the belief we had in ourselves."
Germany are the reigning world champions, having lifted the trophy in Brazil four years ago.