Max Scherzer gave the proverbial middle finger to the callus on his thumb. 

As expected from a three-time Cy Young award winner, Scherzer figured out a way to overcome adversity and pitched six scoreless innings Sunday to start a 5-4 victory against the Guardians in the first game of a doubleheader at Citi Field.

A callus on Scherzer’s thumb that developed during his previous start “split open” and forced him into a season-high reliance on his curveball, with a shifted grip no less. 

“The curveball and changeup were pain-free for me,” Scherzer said. “Because of that, I was able to snap off some good curveballs and use it when I needed it.” 

Throwing for the first time to castoff catcher Gary Sanchez, Scherzer threw 15 curveballs, which accounted for 17 percent of his 86 pitches.

He only threw 10 percent curveballs during his first six starts. 

“It’s raw skin, so it’s a lot of pain,” Scherzer said. “I’ll be good by next start, but you are going to have one start where it’s miserable.” 

Scherzer’s face didn’t hide the misery as he grimaced at times on the mound and initially raised questions about whether he was experiencing some of the shoulder discomfort that he mentioned earlier this month.

But his pitching line — scattering three hits and a walk while striking out five without a runner reaching scoring position — left no hint that something was amiss. 

“Throughout my career I’ve had different injuries and ailments going on and still pitched,” Scherzer said. “That’s when you learn about what you’ve got, what you can do. That’s when you find out what you’re made of — when you go out and compete and win. That almost strengthens you. You get a bounce in your step when you overcome something.” 

Scherzer said he left it up to manager Buck Showalter whether he was needed for the seventh inning but admitted it was “probably the right move” to be pulled early.

Except the bullpen blew a 3-0 lead in the eighth, costing Scherzer the win. 

“He was the difference in the game,” Showalter said. “He would’ve thrown 130 pitches if we needed him to.” 

Scherzer attributed a dip in velocity — only two of his 30 four-seam fastballs reached 94 miles per hour, according to Baseball Savant — to the pain. 

“I look at the other team — they tell me how he is pitching,” Showalter said. “If you are always going to base evaluations on a [radar] gun, you are going to make a lot of mistakes.” 

Scherzer compared the callus to “playing basketball with a sprained ankle.” 

“This is the big leagues,” Scherzer said. “I wish things were easy. It’s usually the opposite. It’s usually really hard. You are not always going to feel good. You are actually going to feel pretty crappy some days. I feel like I’ve been on a string of this. I’m not here to complain about it. You just suck it up, pitch and win.”