Revisiting the ‘very rare’ spectacle of the 2003 Subway Series crosstown doubleheader, which helped make a star of Hideki Matsui

It’s been 20 years since Hideki Matsui made his Yankees debut, and before his clutch hitting over six postseasons vaulted him to a place among the greats in the organization, there was a time as a rookie when Matsui was a slumping slugger, struggling to live up to wild expectations.

Through June 4 of his first season after coming over from Japan, Matsui had played 58 games and hit just three homers — one of them a memorable grand slam in his Yankee Stadium debut — with a .250 average and an anemic OPS of .656.

Then came June 5 in Cincinnati, where Matsui picked up his first four-hit game in the majors with three doubles and a homer.

And a few weeks later, Matsui further cemented himself as a force in the middle of the Yankees lineup with a volcanic showing while playing in both ends of a historic day-night Subway Series doubleheader split between Yankee and Shea Stadiums, following the first such twinbill in 2000.

“I remember it really well,’’ Matsui said by phone through an interpreter of that June 28, 2003 afternoon and evening. “I watched the 2000 Subway World Series in Japan and that was really memorable to me, so to experience something like that myself a few years later was very exciting.”

The day began at Yankee Stadium, where Matsui went 2-for-3 with five RBIs and a grand slam for the game’s first runs in a 7-1 Yankees victory behind eight innings from Roger Clemens.

In the nightcap, a 9-8 win in which the Yankees chased Tom Glavine and took a 9-0 lead before withstanding a furious Mets rally, Matsui went 4-for-4 with a walk and an RBI.

Between the two games, Matsui recalls the trip from The Bronx to Queens as something he never had experienced at home, where he played for the Yomiuri Giants.

“I knew it was going to be a long day and a very rare experience,’’ Matsui said. “To play in two different stadiums in New York City, I didn’t know what to expect. I just wanted to enjoy the day.”

Following the Game 1 win at Yankee Stadium, the Yankees received a police escort to Shea Stadium.

“That’s when I realized how big this was,’’ Matsui said. “That kind of spotlight, with the police escort from one stadium to the other, you could never imagine happening in Tokyo just for a baseball game. It’s something I won’t forget.”

He followed through with another stellar game in the nightcap as the World Series-bound Yankees dominated the sub-.500 Mets.

“I think he’s going to be a great player here,” Joe Torre said that day. “Whether he is recognized as a great player league-wide, I don’t know. I don’t know if you would want anyone hitting with runners on base more than him. That makes him a great teammate and a great producer.”

Matsui proved to be an excellent player, and the doubleheader was  a springboard that got Matsui going at the plate after he signed a three-year, $21 million deal to join the Yankees the previous offseason.

“It was definitely an adjustment period for me against major league pitchers, and that’s something I expected,’’ said Matsui, who turned 49 on Monday. “It took a little longer than I expected, but in my mind, at that time, I wasn’t really thinking about any pressure. But I was hitting fifth or sixth in the lineup, so I may have put some pressure on myself unconsciously.”

He still credits his Hall of Fame manager with helping him get going at the plate.

Earlier that June, Matsui said, Torre gave him two impactful pieces of advice.

“The first one was mental,’’ Matsui said. “He told me, ‘I know you’re not hitting right now, but I’m not taking you out of the lineup.’”

At the time, Matsui was playing center field because Bernie Williams was out with an injury.

The next bit of advice Torre gave, according to Matsui, was technical.

“He talked about where I was in the batter’s box,’’ Matsui said. “He suggested standing a little closer to home plate. I did what he told me, and started to hit.”

Matsui’s career in pinstripes really took off that month, culminating in his heroics in the Subway Series. In the 23 games starting on June 5, Matsui went 39-for-85 (.459) with six homers, 28 RBIs and an OPS of 1.326.

He went on to become a force for most of his six years in The Bronx, finishing with 140 homers as well as a .933 OPS in 235 playoff plate appearances.