In the final, 2012 champion, Abdelaati Iguider jumped out to an early lead, with the American pair of Ben Blankenship and Craig Engels immediately behind him.
Jake Wightman ran out in lane 3 to run around the crowd into third place as Iguider squeezed into the lead on the inside.
Wightman held Lewandowski to the outside of the penultimate turn but on the backstretch, he passed and set off after Tefera and Iguider.
A desperate Iguider began leaning five metres before the finish, but he couldn't hold off Lewandowski speeding past for silver.
Tefera had run significantly faster, setting the World Junior Record in the event at 3:36.05, just 36 days earlier.