Classes at SF State weren’t cancelled Tuesday night, but they probably thinned out a little bit as Giants fans poured into The Pub on campus to watch the Giants take down the Royals in Game 1 of the World Series 7-1.

With all seats taken long before the starting time at 5:07 p.m. and a drink line curling out the door and around the corner, The Pub transformed into a playland of orange and black.

The bar exploded at the sight of Gregor Blanco’s leadoff single and hemmed and hawed at Buster Posey getting thrown out on Pablo Sandoval’s RBI double. But by the time Hunter Pence hit his two-run blast to give the Giants a 3-0 advantage in the top of the first, pandemonium took hold of SF State’s humble little pub.

“I don’t go to school here, but I live down the street,” said 23-year-old Kevin Rucker. He said he hadn’t watched a game at The Pub before, but he loved the atmosphere. “It’s a good crowd. There are a fair amount of Giants fans here, not a lot of fairweather fans.”

Rucker was part of a fairly large and raucous crowd in the back of the bar, leading “Let’s go Giants” chants and hanging on every pitch. 22-year-old Kat Yue was the strong, silent type of the group, watching the game with intent in her black Hunter Pence shirt.

“I work on campus, and plus it’s more fun to watch it here,” Yue said. With all of her roommates at work, she said she sought out fans at The Pub for the game.

While the Giants were working Royals starting pitcher “Big Game” James Shields’ pitch count up to nearly 50 through two innings, Kansas City was putting a little pressure of their own on Madison Bumgarner. Despite throwing only 31 pitches through the first two innings, Bumgarner faced a major jam by loading up the bases in the bottom of the third. The Pub roared as he escaped by forcing first baseman Eric Hosmer to ground out.

“(I was) not nervous at all,” 22-year-old student Davis Hillman said after the inning was over. “I trust Bumgarner. He has always come through and I know he does great in the postseason.”

Hillman’s confidence paid dividends in the next frame, as an onslaught of baserunners chased Shields out of the game, on the hook for five earned runs. The Pub transformed into the left field bleachers at AT&T Park, with “What’s the matter with Shields? He’s! A! Bum!” raining ruthlessly at the television.

“I grew up in LA but my dad for some reason hated the Dodgers,” said Noah Jacobson, who came to the Bay Area in August. “Once I moved up here, I was like, ‘I could be a Giants fan.’ This bar has had a huge influence on that.”

Jacobson said he’s come with his friends to watch almost every game at The Pub, and despite the added pressure of the World Series, it wasn’t at its wildest Tuesday night.

“We’ve been rowdier,” Jacobson said before arguing with his friends over whether the Pirates game or Game 5 of the NLCS took that crown .

The debate came to a close in the top of the seventh, when Joe Panik drove in two more runs to give the Giants a 7-0 lead and put the game all but out of reach. The Pub roared as San Francisco piled on and made it clear that Game 1 was theirs, and the whole crowd sang along to “Don’t Stop Believing” during the seventh inning stretch.

“It all comes down to two things every other year: an awesome bullpen and no one can handle us in October,” said 24-year-old Matvey Voishchev after the final out.

Voishchev said he has been a Giants fan since he moved to the Bay Area from Russia four years ago. “We have something they never have: We’ve been there.”

Plenty of the fans at The Pub had predictions before the game, including Yue, who said the Giants would win in five games, and Jacobson, who called his new home team in six. Still, so may have been swayed by San Francisco’s convincing victory.

“Giants in six is still my prediction, but we’ll see,” Jacobson said, but added with a shrug, “Who knows – it might be five.”