KISSIMMEE, Fla. — Julio Teheran took another step into winning the fifth spot in the Atlanta Braves’ rotation, extending the St. Louis Cardinals’ offensive woes.

Teheran struck out six in five hitless innings and lowered his ERA to 1.29 Tuesday in the Braves’ 12-3 victory.

“He’s been great,” Braves manager Fredi Gonzalez said of the 22-year-old right-hander. “He’s matured. He’s polished himself up a little bit and he’s looking good.”

St. Louis went 29 consecutive innings without a run before scoring three times in the seventh against reliever Luis Avilan.

Teheran has allowed four hits in 14 innings over four starts and has 18 strikeouts and four walks. Of his 64 pitches against the Cardinals, 44 were strikes.

“Julio’s got some weapons,” Gonzalez said. “The more he goes out there the more he’s impressing me with his changeup and a two-seamer that comes back on the lefties.”

Teheran struggled last spring training when given a chance to win a rotation spot and then went 7-9 with a 5.08 ERA at Triple-A Gwinnett.

“He’s up to three, maybe 3 1-2 pitches now,” Gonzalez said. “I wouldn’t have called him more than a one-pitch pitcher last year.”

Still, Gonzalez wasn’t prepared to announce a decision on his fifth starter.

He’s too young for me to say that,” the manager said.

St. Louis starter Jake Westbrook struggled with his control, and relievers Edward Mujica and Jason Motte allowed eight runs in the seventh and eighth innings.

Mujica gave up five runs and six hits — four for extra bases — in the seventh as his ERA ballooned to 15.00. The three runs off Motte in the eighth were unearned.

Evan Gattis had doubles off both Mujica and Motte, driving in three runs. Freddie Freeman was 2 for 2 and drove in two runs.

Westbrook allowed two runs, three hits, three walks and a hit batter in four innings.