Dodgers catcher Russell Martin pitches a scoreless ninth inning in rout of Diamondbacks

The bizarre start to the Dodgers and Diamondbacks’ season-opening series — already setting records with eight Dodgers home runs on opening day and a six-hour, five-minute test of wills Friday — took another sharp turn Saturday night at Dodger Stadium.

Historically, position players usually have been asked to pitch as a last resort in blowouts when the team getting rammed wants to save its bullpen. In the Dodgers’ 18-5 win Saturday, that convention was defied with two catchers reversing roles to different results.

It began in the bottom of the seventh inning with the Diamondbacks trailing 11-3. They had two more turns at bat to overcome the deficit. The odds were long but existent. Arizona threw in the towel anyway. Instead of pushing their depleted bullpen, the Diamondbacks gave the ball to John Ryan Murphy, one of the three catchers on their roster.

Murphy’s arsenal consisted of one pitch. It vacillated between slow and very slow, never climbing above 65 mph, without any movement. The Dodgers loaded the bases but Murphy somehow escaped. The Diamondbacks then scored two runs to trim the Dodgers’ lead to six. Murphy wasn’t as fortunate in the eighth. Cody Bellinger cracked a two-run home run and Austin Barnes also hit a two-run shot. The Dodgers solved Murphy and it became batting practice. They punished the right-hander for seven runs.

“You try to do too much, you’re going to get out like a few people did the first time and we made adjustments the second time,” Bellinger said. “You got to really stay short with those guys. You just got to take advantage with those opportunities.”

As the Dodgers’ bats pounded away, manager Dave Roberts, looking to avoid using another reliever for the ninth inning, approached Russell Martin with a question: Can you pitch?

The 36-year-old catcher answered yes, even though he later estimated he hadn’t pitched in a game in nearly 20 years. He was convincing enough and went down to the batting cage to warm up. The session lasted about three minutes.

“Next thing you know,” Martin said, “I was on the bump at Dodger Stadium.”

Martin outshined his counterpart in his second game as a Dodger since 2010. He got Ketel Marte to swing through his second pitch — a 75-mph fastball that registered as a slider — and take strike two before inducing a groundout on a 69-mph breaking pitch. Martin wasn’t sure what to call it.

“It’s not really a slider, it’s not really a curveball,” Martin said. “It’s an in-betweener, but I want to know what my spin rate is like. Everyone’s talking about spin rate. I wonder if I had a good spin rate.”

He got another called strike against the second batter he faced, Nick Ahmed, who grounded out to shortstop. That brought up Murphy. Martin dialed it up a notch for the clash, reaching back for an 84-mph fastball Murphy fouled off. Murphy lifted the next pitch — Martin’s 10th — to center field for the game’s final out.

Martin looked the part until the very end when he forgot to meet his catcher, Austin Barnes, for the customary celebratory handshake. First baseman David Freese had to remind him to turn around.

“He was our most efficient pitcher so far these three games,” Roberts said.

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jorge.castillo@latimes.com

Twitter: @jorgecastillo