The menace came from the lanky hard-throwing right-hander's pledge to compress his usual seven-inning outing into the one frame he would get against the United States team.
"Basically, I'll give it all in that one inning. Just do six, seven innings' work in one," said Teheran, who went on to allow Jason Kipnis' leadoff home run before retiring his next three batters.
His most impressive pitches came with the captivating Bryce Harper at bat: Teheran set him up with an arresting changeup for strike two, then caught him looking at a fastball for the strikeout.
Being World manager Luis Gonzalez's pick to start this prestigious game meant a lot to Teheran. Gonzalez could've made his choice based on personal scouting: The special assistant to Arizona club president Derrick Hall saw Teheran make his second Major League start right here on May 18 against the D-backs.
Whatever went into the decision, Teheran was "very emotional about it."
"It's a great honor, especially when you consider all the stars we have here in this clubhouse," Teheran said.
Six innings later, Teheran was followed to the mound by Atlanta's other World Team representative, the Dominican Republic's Arodys Vizcaino.
Protecting a 4-3 lead, Vizcaino was lights-out in retiring the side on only six pitches -- three of them to fan U.S. outfielder Wil Myers.
An organization long respected for developing pitchers obviously has a couple of others on the way. Even at 20 years old each, the two guys who were neighbors in the World clubhouse could be short-range "Futures."
"I'm proud to be here representing the [Braves] team. It makes me feel I'm a little closer to the big leagues," said Vizcaino, whose pride was enhanced by being able to turn to his left and see fellow Atlanta rep Teheran. "It's a great thing to be here together. Having [Julio] here also makes me feel more comfortable."
Both came here with high rankings in Baseball America's midseason list of top Major League prospects. Vizcaino was No. 16, a reflection of his rapid and impressive rise from Class A to Double-A. Between Lynchburg and Mississippi, Vizcaino has 83 strikeouts in 84 innings.
Teheran was No. 4, esteem based on the fantastic performance at Triple-A that had already earned him the big league baptismal. With the Gwinnett Braves, Teheran is 9-1 with a 1.79 ERA in 15 starts. He has surrendered only two home runs in 95 2/3 innings.
This meteoric progress by a guy who opened 2010 in Class A and entered this season with a lifetime record of 13-14 in the Minors speaks volumes about the refinements of his raw stuff.