PITTSBURGH -- Facing a bases-loaded, two-out jam in the eighth inning, Marlins manager Don Mattingly elected to go with the pitcher he said was throwing the ball better than anyone in his veteran-laden bullpen. The rub: It was Anthony Bender in easily the highest-leverage situation of his young career.

Unfortunately for Miami, the rookie right-hander couldn’t protect a three-run lead, as the club’s losing skid reached eight in an eventual 8-7 defeat in 12 innings to the Pirates at PNC Park. Miami was unable to avoid its first eight-game losing streak since May 15-22, 2015.

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“He had been really good,” Mattingly said. “Thought that was the best matchup right there, a guy that everyone's kind of calling for to be a back-end guy. We felt that was a good spot for him. He's got possibly the best stuff out there. We thought it was the best matchup.”

The 26-year-old Bender entered Saturday pitching primarily in the middle innings, but his 12 scoreless appearances to open his MLB career (0.67 WHIP) had won Mattingly and his coaching staff’s trust. For example, Bender threw 1 1/3 frames on Wednesday while facing the top part of the Blue Jays’ potent lineup, striking out the side -- Bo Bichette, Vladimir Guerrero Jr. and Teoscar Hernández -- in the fifth.

Bender’s sinker-slider combination has been lethal, averaging 96.9 mph on his sinker (MLB average is 92.9 mph) and a 37.5% whiff rate on his slider (MLB average at 35.6%).

With Miami ahead 5-2 in the eighth on Saturday, Anthony Bass allowed a leadoff double to Ke’Bryan Hayes and walked Bryan Reynolds to open the frame. Following a popout and strikeout, Gregory Polanco reached on an infield single to load the bases.

Mattingly turned to Bender, who proceeded to issue a full-count walk and a hit-by-pitch. It appeared the Marlins would get out of the inning with a one-run advantage when Michael Perez sent a grounder to first. Jesús Aguilar fielded the ball and threw over to Bender, who dropped it and allowed two runs to score to make it 6-5 Pittsburgh. Both Mattingly and Pirates starter Chase De Jong believed the game might’ve sped up on Bender.

“We were fortunate, but the one thing about it is we put the ball in play, and when you put the ball in play, anything can happen,” Pirates manager Derek Shelton said. “I think we saw it in that situation. When you extend at-bats, at some point, a pitcher’s going to make a mistake, and our guys did a good job of grinding through. [Kevin] Newman did a good job of grinding through it, and then we get a mistake, and we capitalize.”

Dylan Floro, Miami’s usual setup reliever, instead worked a perfect ninth after a Marlins rally. He had thrown 40 combined pitches on Wednesday and Thursday, when he surrendered the go-ahead runs in the eighth. Yimi García allowed the game-tying sac fly in the 10th with the help of the automatic runner, marking his third straight outing giving up a run and his second consecutive blown save. Adam Cimber, Miami’s seventh reliever of the game, gave up the walk-off single to Jacob Stallings in the 12th.

More than Bender’s fielding error in the eighth, Mattingly singled out not making the Pirates earn their runs as the ball never left the infield. Miami’s bullpen has the second-fewest walks (67) in 2021, but the relief corps has 13 during the eight-game skid. Entering Saturday, it had allowed the fourth-highest wOBA (.358) over the past seven contests.

“I think everybody's starting to see the effects of what we've done early and how we've used those guys, so Donnie and I talked about it,” pitching coach Mel Stottlemyre Jr. said before the game. “We did show up every day and try to win ballgames, trying to juggle the rotation, keep guys healthy and bring guys up and down to fill in. And they've certainly done a good enough job to keep us in games, but we've found ourselves going to the bullpen quite often. And at some point, that starts to show, and that's where we're at a little bit right now. We've got to work through that.”