Probably everyone attending the Austin City Limits Festival has a favorite act on the bill. For me in weekend one, it was Weyes Blood, the stage name of Sub Pop recording artist Natalie Mering. Slotted at 5 p.m. Friday on the BMI Stage, one of the fest's smaller stages, Weyes Blood was more underdog than blockbuster. But the spell she cast in her hourlong set was magic, easily the most musically compelling performance of my long and varied opening day in Zilker Park.

Rail-thin in a white pantsuit — she removed the jacket midset to reveal, amusingly, a T-shirt emblazoned with a movie-poster image from Tom Selleck's 1984 box-office flop "Lassiter" — Mering led her four-piece band through a richly melodic and deeply affecting set that served as an ideal calm-before-the-storm shortly ahead of ACL Fest's headliners.

Switching between keyboards and acoustic guitar, and sometimes just singing, she mixed songs from this year's "Titanic Rising" with selections from earlier albums on the indie label Mexican Summer, plus a stunning cover of Procol Harum's 1967 classic "Whiter Shade of Pale" that proved perfect for the breathtakingly high flights of her voice. She dedicated that tune to the handful of baby-boomers in an audience that was made up largely of younger listeners (the median age was probably under 30).

The key to Weyes Blood's success is a deep musical sophistication that somehow flows out quite naturally and easily. The graceful twists and turns in her songs rival those of 20th-century masters such as Harry Nilsson or Jimmy Webb, though her spectacular voice suggests a closer parallel to Canadian chanteuse Jane Siberry or her Sub Pop labelmate Zoe Randell of the duo Luluc.

From the instantly appealing bouncy pop of "Everyday" to the haunting heartache of "Seven Words" to the uplifting "Something to Believe," Weyes Blood consistently connected with music that's so intimate it's probably best suited to indoor venues, yet still transcended in a festival environment. I'm not sure I'll see a more enchanting vocalist at this year's ACL Fest except perhaps weekend-two-only act Yola (a.k.a. Yolanda Quartey).