Like many musicians, guitarist Berta Rojas can play only music she loves. She said as much to the audience of her Saturday night recital at the Westmoreland Congregational Church in Bethesda, where she sat perched atop a kind of dais for the final event of the John E. Marlow Guitar Series season.

She was talking about the music of Manuel Ponce, the Mexican composer from the first half of the 20th century, to whom the first half of her program was dedicated. Ponce was a chameleon-like composer, fluent in a range of styles (five of his six guitar sonatas bear descriptive labels such as “classical,” “romantic” and “of Paganini”), who did much to expand the classical guitar literature, in large part due to his friendship with Andres Segovia.

Rojas took up Ponce’s music at the instigation of Regis Ferruzza, a spiritus rector of the Marlow series, who assured her that she would indeed love Ponce. “And now,” she told the public, “I do.”

From the evidence, though, it is a shy love, marked less by passion than respect. Later in the evening, Rojas described Ponce as intellectual, contrasting him to the living composers on the second half of the program, whose music came from the heart. That statement certainly described the way she approached both halves of the program — for the first, she was proper; the second, herself.

Make no mistake, Rojas is a lovely guitarist. And she certainly didn’t sound stiff or formal in the Ponce works. Indeed, she approached the first Suite in A Minor, which was specifically written for Segovia to palm off as a baroque work (the two deliberately misattributed it to the brilliant 18th-century lute player Silvius Leopold Weiss), with a sinuous, silky legato. Rather than the stereotypical mechanical evenness of the baroque, her playing teased out the work’s underlying Latin American flavors and 20th-century origins.

And the quasi-conversational tone of arrangements of two of Ponce’s popular songs, including his famous “Estrellita,” carried over into her playing of Sonata III for guitar. Ponce’s only guitar sonata without a descriptive title, this piece shows what may be his most authentic voice: It is direct, sophisticated music of uncertain tonality but great expressiveness. Rojas played it with the earnestness befitting a serious classical work, though her underlying tenderness kept breaking through. At the piece’s end, when the composer throws on the brakes with a sequence of sustained pauses that change the music’s mood entirely, from a dancing allegro to a wistful coda, Rojas, during the rests, looked at the guitar with quiet encouragement, as if waiting to see what it was going to do next.

The second half of the program conveyed a palpable sense of relief, as if corsets had been loosened, shoes kicked off, hair let down, or simply more familiar music allowed back into the guitarist’s fingers. (There were a few bobbled notes on the first half but virtually none on the second.) The pieces were smaller in scale, intimate, less formally ambitious. Vincent Lindsey-Clark’s appealing little “Laura” was meant to evoke the playing of his small daughter; Edin Solis offered borderline easy-listening music with “Preludio” and a kinetic “Danza”; Byeong Woo Lee, a successful film composer in Korea, wrote a racing “Run I,” which Rojas also tamed with her gentle lissome touch. All of these composers — as well as Quique Sinesi and Egberto Gismonti, whose music was also featured — are in their 40s and 50s, and the sense of a living tradition helped enliven the proceedings.

For the encores, Rojas returned to her literal and figurative home base: the music of Agustin Barrios, also active in the first half of the 20th century, whose work she has in some cases exhumed, championed and recorded. The energy here left no question as to which composer truly has Rojas’s heart. Still, the exposure to Ponce was beneficial to all concerned. Ferruzza, alas, came down with pneumonia and didn’t get to hear it.