“Welcome to the second century of the San Francisco Opera,” said General Director Matthew Shilvock, and suddenly the magnitude of the occasion sank in afresh.

Here is a company that has devoted 100 years to both this city and this art form, and it’s poised to do the same for another 100. How marvelous.

The season-opening gala concert on Friday, Sept. 8, may not have provided the kind of genre-bending thrills that audiences got a year ago, whentenor Pene Patiunexpectedly launched into a traditional Māorihakadance on the stage of the War Memorial Opera House. This was a far more traditional undertaking, with two established stars of the field — the married team of Polish soprano Aleksandra Kurzak and French tenor Roberto Alagna — partnering with the San Francisco Opera Orchestra and Chorus under Music DirectorEun Sun Kimto reel off a string of familiar operatic excerpts and a few popular bonbons.

But even in a retro configuration, and even without the full narratives that give this music meaning, opera still has the ability to summon up primal emotions in their raw form. It draws us in with its expressive power, and unleashes the full range of human experience.

• Photos:San Francisco Opera kicks off 101st season

You could hear that in the fiery confrontation from Mascagni’s “Cavalleria Rusticana,” in which Kurzak and Alagna got a sprightly assist from Adler fellow Olivia Smith. You could hear it in the sumptuously beautiful orchestral Intermezzo from the same opera, which Kim shaped with preternatural depth and grace.

你能听到它最重要的是“你,你,埃莫e? Tu?”, the duet from Act 2 of Puccini’s “Manon Lescaut,” which brought out the most focused and dramatically charged performance of the evening from the two stars.

Not all the emotion was confined to the stage. Shilvock’s mention of Rep. Nancy Pelosi, who was in the audience on the day sheannounced her plansto run for reelection, drew tumultuous applause mixed with a smattering of audible boos from the audience.

In general, the program also served as an opportunity for those who love the art form most deeply to share it with those still learning to do so.

Doug Del Paggio said he has been attending opening nights for more than 30 years. He had mixed feelings about the company’s newly stretched-out schedule for opening its season, a contrast to thelong-standing practiceof cramming two full operas and Opera in the Park into a single dense weekend.

“I liked OD’ing on opera in the old days,” said the San Francisco resident. “I enjoyed coming here on Friday night, and then Saturday night, and then Opera in the Park. Because I really missed opera by the time the season started.”

On the other hand, the new plan is perfect for introducing newbies like his friend Brian Hamway, whom he described as an “opera virgin.”

“This is a pretty easy way to begin,” Del Paggio said. “Taking someone that hasn’t been here a whole lot to a full-length opera is sometimes a little overwhelming.”

Parents can do their part as well. San Francisco patrons Alexandra Siliezar and Alla Bolsheva were on hand with their 12-year-old daughters, Paloma Siliezar andAlliana Lili Yang, both of whom are among the company’s corps of child supernumeraries and pursuing singing careers.

“Opera is one of the most important art forms we have in San Francisco and even in the world,” said Alexandra Siliezar. “So I believe we need to support it and bring the next generation along.”

Yang is due to appear in the company’s production of “Il Trovatore,” which opens Tuesday, Sept. 12, with sopranoAngel Blueas Leonora. In the meantime, though, they were able to savor the contributions of the evening’s two luminaries.

Kurzak has appeared in San Francisco once before, making a memorable 2012company debutas Gilda in Verdi’s “Rigoletto.” Alagna, in spite of a career as one of the world’s most notable tenors, had yet to set foot in the War Memorial until Friday night.

But this was probably not the ideal format in which to encounter either singer. Kurzak’s rendition of “Vissi d’arte” from Puccini’s “Tosca” sounded full-voiced but dramatically unmoored. Alagna’s renditions of excerpts from Saint-Saëns’ “Samson et Dalila” and Leoncavallo’s “Pagliacci” were commanding yet blunt.

The two singers seemed most at ease in a series of popular favorites, including the Mexican standard “Cielito Lindo,” the Neapolitan standard “Funiculì, Funiculà,” and “Libertà,” a sweet-toned ballad written by Alagna’s brother David.

In “Lippen Schweigen,” from Franz Lehár’s operetta “The Merry Widow,” they delightfully jettisoned the original German words to sing to one another in what Shilvock called their “language of love”: Alagna held forth in his native French, while Kurzak replied in her native Polish.

It was an evocative moment, exemplifying the flexibility and communicative power of opera, even across linguistic boundaries. The remainder of the season promises to delve into that notion at even greater depth.

Correction:An earlier version of this article referred incorrectly to two 12-year-old attendees. Only one, Alliana Lili Yang, is slated to appear in the company's upcoming production of "Il Trovatore."

Reach Joshua Kosman:jkosman@sfchronicle.com; Twitter:@JoshuaKosman