And we all thought this was just another Wednesday night game against the Houston Astros.

Matt Cain pitched a perfect game.

And this is perhaps the most difficult kind of post to write, because now I expect perfection from myself. Good luck with that.

I’ve been lucky enough to watch a bunch of games from the press box this season, and Wednesday night was the second time in 2012 that I’ve attended a game in my normal AT&T Park clothes: Giants shirt, Giants hat, black and orange Air Max 95s. (What, you thought I wasn’t a homer?) But even before he threw the best game any of us will probably ever see again from a Giants pitcher, the running theme throughout this entire season — from the surprise contract extension just before the season started up until Wednesday night — has been: Matt Cain.

There’s a certain no-hitter template I think every fan knows, but it’s impossible to follow unless you’re kind of oblivious — it’s supposed to sneak up on you, hit you with a wave of “wait, do I have the power to jinx this” thought patterns, then sweep you off your feet. Maybe jinxes don’t exist (and Cain’s perfect game proved that once and for all, at least for me and the 40,000 who attended the game), but I still believe that if you’re transfixed on the scoreboard and staring at those zeroes too early, you’ll spook the thing.

With all the hits and homers and runs and everything else, I was blissfully unaware that Cain was working on a no-hitter. That’s what happens when you’re sitting in Section 103, Row 5, Seats 5-8* with your wife and two friends (and some food and beverages that will go unmentioned). You watch the game, cheer when Melky Cabrera and Brandon Belt hit home runs, and marvel at the blowout.

Then I glanced at the scoreboard in the 6th inning and realized Cain wasn’t just racking up strikeouts … he was marching toward history.

What was it like to watch Cain’s perfect game in the stands? First, it’s humbling to know we just saw something only 19 other crowds have witnessed since 1900. Second, AT&T Park felt like 2010 again — strangers were high-fiving each other and, for the first time in over a year, the crowd rose to the occasion and became part of the action again.

It was only an inning after I realized what we were watching when Gregor Blanco made the dive that, around here, will be remembered along with catches from Willie Mays and Dwight Clark. Once Blanco came down with the ball and Cain raised his arms like Joe Montana after a touchdown, picturing history in front of our eyes became extraordinarily easy.

After watching Cain’s one-hitter on the home opener, followed by his battle with Cliff Lee, I figured it might only be a matter of time before Cain finally broke throw and hurled his first no-no. But then again, who was to say Cain would ever do it? After all, around these parts “Getting Cained” is the expression for pitching brilliantly and having nothing to show for it.

Cain has so much to show for his career already — and the financial part isn’t even what I’m getting at. Without Cain, the Giants don’t start a run of fantastic, homegrown pitchers. Without Cain, the Giants don’t win their first World Series in San Francisco. Without Cain, the Giants don’t have a perfect game.

I wrote about Cain’s Cy Young resume after his last start, and it felt a little premature. Not anymore.

* That’s where I stood while filming the video at the top with my cellphone.