Teheran (10-6) scattered five hits, walked three and struck out five, tossing 66-of-105 pitches for strikes.
David Carpenter and Jordan Walden combined for 1 2/3 scoreless innings of relief and Craig Kimbrel struck out the side in the ninth for his 39th save as the Braves improved to 76-48, the best mark in baseball.
Washington's Gio Gonzalez (7-6) absorbed the loss, yielding a pair of runs on five hits over seven innings. He walked four and struck out nine.
Jayson Werth supplied the only RBI for the Nats, who dropped 2-of-3 to the Braves.