What’s the secret to Clayton Kershaw’s opening day dominance? He’s Clayton Kershaw.

Across half a dozen starts on opening day, Clayton Kershaw has thrown 526 pitches in 38 2/3 innings. He has faced 144 batters and struck out 44. He has hit a home run and allowed none. He has pitched a shutout once and allowed a run twice. He has never lost, and neither have the Dodgers.

Yet the moment he remembers most from these six outings involves an incident of physical infirmity, on a day when he had “never felt that bad and tried to pitch before.” It occurred in the season opener in 2012, at San Diego. A stomach virus sapped his strength. He realized the depth of his illness after hitting a double in the third inning.

“I got to second base, and I was like ‘I can’t go anymore,’” Kershaw said. “And I just threw up the rest of the night. It was either food poisoning or just a really bad stomach virus. But I was a mess.”

Otherwise the details coalesce into a blur of missed bats and brief innings. Kershaw is dominant on most days, but he has been particularly transcendent at the outset of each season, with a 0.93 earned-run average in those six games. His seventh awaits him Monday afternoon against the Padres at Dodger Stadium.

When Kershaw picks up the baseball a few minutes after 1 p.m., he will tie a franchise record for opening day starts shared by Don Drysdale and Don Sutton. The list of his predecessors feels like a collection of relics from another age: Vicente Padilla in 2010, Hiroki Kuroda in 2009, Brad Penny in 2008, Derek Lowe in 2007. Kershaw is almost halfway to reaching the major league record, which Tom Seaver set by starting 16 openers for the Mets, Reds and White Sox. Jack Morris owns the mark for consecutive starts with 14 for Detroit.

At 29, now in his 10th season as a Dodger, Kershaw enters 2017 nine months removed from the herniated disk that derailed his summer and nearly ended his 2016 season. He recovered in time to pitch last September and October, but he will spend this season amid heightened scrutiny over his condition.

Kershaw retooled his weekly routine as he rehabilitated last year, and he carried that program into the winter. Manager Dave Roberts remarked this spring that Kershaw betrayed no hints of his previous injury. When the season begins Monday, Roberts said he plans to treat Kershaw like he always has.

“He’s where he has been, in my assumption, in past opening days,” Roberts said.

With that in mind, here’s a glance at how Kershaw has fared on this assignment in the past.

1. March 31, 2011, at Dodger Stadium

Dodgers 2, Giants 1.

Kershaw’s line: 7 innings, 4 hits, 0 runs, 1 walk, 9 strikeouts.

For seven innings, Kershaw dueled with Tim Lincecum, the two-time National League Cy Young Award winner. At this point in his career, two weeks after his 23rd birthday, Kershaw had not yet received a vote in the Cy Young balloting. That changed in 2011, when he bested the Phillies duo of Roy Halladay and Cliff Lee to secure the first of his three awards.

He started his campaign in overpowering fashion. Kershaw allowed only one Giant to reach second base. He defused a pair of singles in the sixth inning by inducing a double-play ball off the bat of San Francisco first baseman Aubrey Huff. And he returned for a 1-2-3 seventh inning to hold the lead.

2. April 5, 2012, at Petco Park

Dodgers 5, Padres 3.

Kershaw’s line: 3 innings, 2 hits, 0 runs, 1 walk, 3 strikeouts.

Racked by illness, Kershaw saw his fastball velocity sink into the upper 80s during his brief outing. Behind the plate was catcher A.J. Ellis, Kershaw’s friend and longtime battery mate, who was making his own first start on opening day.

“A.J. was like ‘I had no time to be nervous. I was so worried about you,’” Kershaw said.

Kershaw did not remain ill for long. He pitched again five days later, struck out seven Pirates in seven innings of one-run baseball and finished the season second in Cy Young voting.

3. April 1, 2013, at Dodger Stadium

Dodgers 4, Giants 0

Kershaw’s line: 9 innings, 4 hits, 0 runs, 0 walks, 7 strikeouts.

Distance has always mattered to Kershaw. He loathes the prospect of relinquishing the baseball, and since 2011, no pitcher has been more proficient at giving his bullpen the day off. In the last six seasons, Kershaw has thrown 23 complete games; no other pitcher has thrown more than 18. He has spun 14 shutouts; no other pitcher has cracked double digits.

With the game scoreless in the eighth inning, Kershaw led off with a home run against San Francisco reliever George Kontos. It remains the only homer of his career. His teammates tacked on three more runs, which gave Kershaw time to refocus in the dugout. He worked around a single in the ninth to complete his sixth career shutout.

4. March 22, 2014, at Sydney Cricket Grounds

Dodgers 3, Diamondbacks 1

Kershaw’s line: 6 2/3 innings, 5 hits, 1 run, 1 walk, 7 strikeouts.

The oddity of this outing, which occurred nearly two weeks before the rest of MLB started the season, on another continent, 15 hours away from Dodger Stadium, only increased in the days afterward. Kershaw showed few signs of distress in the victory. He left in the seventh, with a runner aboard, and reliever Chris Perez picked up the last out in the inning.

The receipt arrived after the Dodgers returned to America. Kershaw felt soreness in his upper back while playing catch. He missed the entirety of April. The injury, of course, only added to the magnitude of his accomplishments for the season, when he won his third Cy Young award and his first most valuable player trophy, going 21-3 with a 1.77 ERA.

5. April 6, 2015, at Dodger Stadium

Dodgers 6, Padres 3

Kershaw’s line: 6 innings, 6 hits, 3 runs, 2 walks, 9 strikeouts.

This outing set the stage for Kershaw’s strange flirtation with mortality, when he posted a 3.86 ERA in the first two months of the season. His ERA shrunk to 1.45 during his final 23 games, and he struck out a career-best 301 batters.

But Kershaw did exit this particular game, in which he gave up a pair of run-scoring hits to former teammate Matt Kemp, in line for a loss. His teammates bailed him out. Howie Kendrick hit a game-tying double in the seventh and Jimmy Rollins supplied a three-run homer in the eighth. The Dodgers’ perfect record with Kershaw on the mound in openers stayed safe.

6. April 4, 2016, at Petco Park

Dodgers 15, Padres 0

Kershaw’s line: 7 innings, 1 hit, 0 runs, 1 walk, 9 strikeouts.

The 2016 season would prove to be a campaign packed with adversity for both Kershaw and the Dodgers. On this day, at least, there was no sign of the strain to come. The lowly Padres looked futile and Kershaw breezed through the outing. He maintained the pace all the way until the end of June, when he succumbed to the discomfort in his back. Kershaw did not pitch again until Sept. 9.

Upon his return, Kershaw generated ample velocity on his fastball, but displayed intermittent command of his curveball and his slider. The pitches looked more cooperative in the Cactus League this spring, and Roberts wasted little time in announcing his starter for opening day. To the shock of no one, he chose the man who has never lost an opener.

“It’s always nice to get off to a good start,” Kershaw said. “There’s jitters for everybody. It’s the first time you’ve pitched in front of a crowd, first time the game counts, all that stuff. Once you get settled in, same old stuff.”

andy.mccullough@latimes.com

Twitter: @McCulloughTimes