The Red Sox got their first look at this year’s new extra-innings rule on Saturday. Like most other things this season, it didn’t go very well for Boston.

Despite scoring a run in the top of the 10th, the Red Sox gave up a pair in the bottom of the inning, dropping a 5-4 decision at Camden Yards that ended Boston’s season high three-game winning streak.

• Box score

“It was our first action with it and it was interesting,” manager Ron Roenicke said despite the final score. “I kind of liked it. You get after it right away and you try to figure out what you're going to do.”

Matt Barnes -- who became the de facto closer when Brandon Workman was traded to the Phillies on Friday night -- took the loss after blowing the save opportunity.

The Red Sox were four outs from extending their winning streak, as Josh Taylor had two out and nobody on with a two-run lead in the eighth. Hanser Alberto drew a walk, setting up Anthony Santander’s game-tying two-run home run.

As the game moved to the 10th, it gave the Red Sox their first look at the new 2020 rule that puts an automatic runner at second base to start each extra inning. The Red Sox didn’t have to do much to bring the go-ahead run home, as Orioles closer Cole Sulser issued three straight one-out walks to J.D. Martinez, Xander Bogaerts and Mitch Moreland, scoring Alex Verdugo for a 4-3 lead.

“Once we score the one run, it's up to them; do they try to tie it with a bunt or what do they do?” Roenicke said. “They had the right guy up.”

The “right guy” was the speedy Cedric Mullins, who laid down a perfect bunt toward first base. Moreland fielded it and fired to third, trying unsuccessfully to throw out Rio Ruiz, who had opened the inning at second base.

“I'd rather have him go to first,” Roenicke said. “It was such a tough bunt that he's going to have to spin and throw it to first with a guy who's flying down the line. You’d prefer to try to get one out at least; if you can get the first guy, you do. But you couldn't lay down the ball any better than he bunted that. … We didn't get any outs on the play, which really hurt.”

Barnes unleashed a wild pitch on a 1-2 curveball to Alberto, bringing Ruiz home to tie the game, 4-4.

“You see the bunt go down and all of a sudden you're first-and-third with no outs,” Roenicke said. “That's a tough spot for anybody.”

Alberto reached on an infield single, then the Red Sox intentionally walked Santander to load the bases. Barnes struck out Andrew Velasquez for the first out, but Pedro Severino lined a single to center field, scoring Mullins on the first walk-off hit of his career.

Though he didn’t factor into the decision, Martín Pérez continued his steady season, something that can’t be said for most of the Red Sox rotation. The left-hander allowed one run on five hits and one walk over seven innings, striking out six. Pérez became just the second Red Sox pitcher this season to go seven innings in a start, joining Nathan Eovaldi, who accomplished the feat on Thursday.

“The last two outings we got from Nate and then from Martín, they were outstanding,” Roenicke said. “Seven innings, great job; he commanded the ball all night. It's just too bad we didn't get him a win.”

Verdugo shined in the field and at the plate, throwing a runner out at home to end the fourth inning while going 2-for-5 with two doubles and an RBI. Verdugo extended his hitting streak to 13 games, hitting .327 (17-for-52) with 10 extra-base hits during the streak, the second-longest in the Majors behind Santander, whose streak now stands at 17.

In the end, it was another loss for the Red Sox -- one that came in a different form than any other this season.

“It was weird; I feel like we were playing Little League,” Pérez said. “But those are the rules and we have to follow the rules. In the 10th inning, they played better than us.”