For Jesse and Margaret McDonald, Saturday's Rock the Garden concert outside Walker Art Center felt like something of a musical reprise.

"We did Bonnaroo last weekend, and this seemed like a good way of keeping that vibe going," said Margaret McDonald, 32, of St. Paul, referring to the big kahuna of U.S. summer rock fests in Tennessee, where they saw one of Saturday's RTG performers, Courtney Barnett. "We really wanted to see her again," Jesse McDonald added.

Rock the Garden is small compared to Bonnaroo, but it remains one of the Twin Cities' biggest and hippest music festivals. More than 9,000 fans sprawled on the Walker's grassy slope Saturday, and even more are expected Sunday — about twice the total attendance from the years before 2014, when the event expanded into a two-day festival after its one-day lineups consistently sold out.

A membership drive event for its nonprofit co-organizers Walker Art and Minnesota Public Radio — whose modern outlet 89.3 the Current sets the musical template — Rock the Garden set itself apart from the other Twin Cities summer fests from the get-go Saturday, when local electro-psychedelic hip-hop/R&B quartet theStand4rd kicked things off. "Sun baked" took on a double meaning in the case of the young group's mellow-cool, hazy half-hour opening set.

Brooklyn's harmonious jangle-pop quintet Lucius followed with a much more coherent and warmly received set in which co-leaders Jess Wolfe's and Holly Laessig's matching gold dresses competed with the sun for brightness.

"This is what Rock the Garden is all about," said Anastasia Preston, 22, of Minneapolis. "A band I'd never seen before blowing me away."

Scottish indie darlings Belle & Sebastian and Omaha's celebrated songwriter Conor Oberst rounded out Saturday's lineup with Barnett. The fest continues Sunday with "Float On" hitmakers Modest Mouse for headliners and reunited '90s thrash-punks Babes in Toyland for hometown favorites, plus JD McPherson, Seun Kuti & Egypt 80 and Sean Lennon's Ghost of a Saber Tooth Tiger. Tickets should be available at showtime, 3:45 p.m., for $64.

Chris Riemenschneider • 612-673-4658