Hernandez allowed one run and five hits with two strikeouts and no walks in seven innings. In his previous start, he gave up one run and three hits in six innings and retired 16 of his last 17 batters in a 2-1 loss to the New York Yankees.
Two strong games against two of baseball's best teams in their home stadiums by a pitcher who has just seven major league starts, all this season.
"Hernandez is special," Orioles coach Dave Trembley said. "For him to come in here after he pitched in Yankee Stadium says a lot about how far he's come and what he means to our future."
Hernandez (3-2) had an outstanding fastball and gave up three earned runs or less for his fifth straight start. Smoltz (1-4) has allowed at least five runs in four of his six starts in his first year with Boston following offseason shoulder surgery and 20 years with Atlanta.
"I'd walk away from the game right now if I didn't think I could do what I can do," Smoltz said. "There's no thought in my head of that right now."
Nick Markakis, batting cleanup for the first time this season in place of slumping Aubrey Huff, did the most damage with a sacrifice fly in the first inning, an RBI double in the third and a solo homer in the fifth that gave the Orioles a 6-0 lead.
"Just making him get the ball over the plate," Markakis said.
Smoltz did that too much.
"This is going to work," manager Terry Francona said. "As his results get better, I'm sure he'll feel better. He's frustrated. He's been getting beat by fastballs that weren't locating."
Smoltz, the only pitcher in major league history with at least 200 wins and 150 saves, described himself as "a fighter ... not a quitter."
And he's gotten positive feedback.
"My fastball, everybody has told me -- unless they're lying -- that its good enough," Smoltz said, but "I'm getting to the point where I've got to put a string of [good] games together."
He gave up six earned runs and nine hits in five innings and increased his ERA to 7.03. He struck out six and walked one.
The Orioles won at Fenway Park for the first time since July 11, 2008.
"It's one more negative thing that people can cross off because what we're all about is being positive," Trembley said, "understanding that we have young players, showing a lot of perseverance."
Smoltz was in trouble from the start.
Melvin Mora was stranded at third in the second, the only inning in which Smoltz held the Orioles scoreless. But the right-hander couldn't escape a two-out jam in the third.
Roberts started the inning with a single and was forced out at second on Pie's grounder. Pie took second on a groundout by Jones. Then the Orioles scored three runs on the next four pitches with RBI doubles by Markakis and Nolan Reimold and a run-scoring single by Ty Wigginton.
Pie made it 5-0 with an RBI double in the fourth before Markakis hit his 12th homer of the season.
Hernandez, meanwhile, retired Boston's first nine batters on just 35 pitches.
"I was trying to focus on getting out of the first inning quickly because that's been my downfall," he said. "It was good to have a quick inning. It settles you down."
Jacoby Ellsbury led off the fourth with a ground ball single that bounced off second base and into short left field. Ellsbury stole his 44th base of the year and took third on a fly out but stayed there when David Ortiz flied out for the third out.
LaRoche, obtained from Pittsburgh last week, started at first base the day after homering in his Red Sox debut. Kevin Youkilis started at third and Mike Lowell got the day off. ... Baltimore's 16-34 road record is the worst in the AL. ... Orioles shortstop Robert Andino struck out on each of his first three at bats and grounded out to the pitcher on his fourth. ... Boston relievers have held opponents scoreless since the All-Star break, a stretch of 22 innings. ... Ellsbury stole his 103rd base, breaking a tie for 10th place in Red Sox history with Jimmy Collins and Duffy Lewis.