BALTIMORE -- Credit the kids for this one.

Rookies Shed Long and Kyle Lewis continued their scorching Septembers with big days at the plate on Saturday and shortstop J.P. Crawford ripped a three-run homer in the eighth, as the Mariners’ young guns provided the punch in a 7-6, 13-inning victory over the Orioles at Camden Yards.

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Another rookie, Tim Lopes, drove in the go-ahead run with an infield single with two out in the 13th, as Mallex Smith alertly sprinted home from second on a high chopper that Lopes narrowly beat out on a high throw from third baseman Rio Ruiz.

“With an opportunity like that, I had no plans on stopping,” said Smith, who had reached on an error and then swiped his 45th base to put himself in position. “The third baseman playing back, chopper, I’m outta there.”

Smith’s heads-up play wound up deciding the four-hour, 42-minute battle after rookie reliever Erik Swanson -- the Mariners’ 10th pitcher of the night -- closed out the 13th for his second save.

Smith, who is only 26 himself, credited his younger teammates with providing a boost in the Mariners’ late-season run, with Seattle winning eight of its past 11 games.

“These last few weeks, they’ve just kind of carried us,” Smith said. “They’ve done a phenomenal job. Great at-bats, hitting the ball hard, getting key hits when we need ‘em. It’s been fun to watch and it gives us a bright spot for the future.”

Long, who has been primarily playing left field since being called up from Triple-A Tacoma on Sept. 2, went 3-for-4 with a homer, a double and a walk while scoring three runs from the leadoff spot. The 24-year-old is batting .414 (17-for-41) with eight RBIs and six extra-base hits over his past nine games.

Lewis, who ripped six homers in his first 10 games since being promoted from Double-A Arkansas, was kept in the yard this time. But the 24-year-old right fielder went 2-for-5 with a pair of opposite-field singles and worked an 11-pitch walk in his six plate appearances to put his average at .333 (15-for-45) with 12 RBIs.

Crawford capped it all with a 3-for-5, four-RBI game, including his line-shot home run in the eighth off reliever Mychal Givens, completing a banner day for the three youngsters at the top of Seattle’s lineup.

“Our guys have a lot to play for,” Mariners manager Scott Servais said. “They’re trying to prove themselves in this league and on our team. It’s been really good. Shed Long had another huge night.”

Crawford’s homer and RBIs were his first since Aug. 23, as he snapped a streak of 48 at-bats without driving in a run with a fifth-inning single and then tied his career high of four RBIs with his three-run shot.

“J.P. Crawford looked awesome tonight at the plate,” Servais said. “He’s been working really hard, making some adjustments in his set-up. Seeing him catch up to that high fastball tonight was great.”

The rest of the Mariners managed just three hits in 36 at-bats and went 0-for-3 in bases-loaded opportunities, but Seattle improved to 4-1 on its final road trip of the season and 66-89 overall. The Orioles missed an opportunity to win back-to-back games for the first time since late August, while falling to 50-105.

Justus Sheffield, another rookie, allowed four runs on five hits in 4 1/3 innings as he remained 0-1 with a 5.81 ERA after six starts. Sheffield said he left too many balls over the plate in a three-run second inning and again in the fifth, when he allowed three hits and a run before reliever Brandon Brennan bailed him out of a bases-loaded, one-out situation.

But the 23-year-old did take a step forward in one area as he continues developing his game at the big league level.

“I threw a lot of changeups. That was about the only positive I took out of tonight,” Sheffield said. “I had some strikeouts on the changeup, so that was good to see. I’ve been focusing on it since I’ve been up here, working on that third pitch. I’m seeing some positive results from throwing it. But they got to me early in the second and I just wasn’t able to get out of the fifth.”