What a difference a horn section, rehearsal and two weeks make. After unveiling her forthcoming album and new band to invited media two weeks ago at Paisley Park, Judith Hill returned there late Saturday night for a “dress rehearsal” show.

She is expected to open for Prince this week in Detroit and also do some club shows.

Hill and her band – its moniker to be announced later – improved about 200 percent in two weeks even if they took a staged and silly timeout after playing the first line of the first song, “As Trains Go By.”

Having a trombonist, trumpeter and two saxophonists from Prince’s NPG Horns made a world of difference. So did rehearsal and Hill’s increased confidence. She’s no rookie, having opened tours for Josh Groban and John Legend and sung backup to Michael Jackson, Stevie Wonder and Elton John. But she sang her funk-oriented songs like she owned them.

Playing in front of 150 or so people in the NPG Music Club room for 45 minutes, Hill and her nine sidemen breezed through a handful of selections from her Prince-produced “Back in Time” album. (Its release date is unknown but it was made available for free download for two days last month and more than 150,000 downloads were recorded, according to Hill.) The set is clearly intended for an opening act but it was a strong sample of her vocal abilities and affinity for funk.

The opening “As Trains Go By” was a commentary on urban violence, with a chorus including an oblique reference (more a play on words) to CeeLo Green, a coach on “The Voice,” where Hill made the finals in 2013. (She was on Adam Levine’s team.) “Turn Up” showed her mastery of hip-hop cadence for sung vocals and love of Sly and the Family Stone jazzy horn-flavored funk. “Angel in the Dark” was balladry with a churchy ending. “My People” featured a nice exchange between bassist and horn players and a delightful detour into “No Diggity,” Blackstreet’s 1996 hit.

“Wild Tonight” had Prince’s funk-rock fingerprints all over it. With Prince giving orders to the sound engineer at the mixing board, Hill next moved into “Cry Cry Cry,” a killer blues in the spirit of Etta James that demonstrated Hill’s wondrous vocal abilities. The group closed with “Jamming in the Basement,” a workout that lives up to its title.

With the advertised Hill rehearsal over, the audience instantly migrated to Paisley’s adjacent soundstage, hoping for a Prince performance. After an hour of a DJ playing songs by Prince, Luther Vandross and others, Prince came running out of a back door headed to the stage. He instructed the DJ to play tunes from Hill’s album. Then, after the DJ essentially played the recorded versions of the tunes Hill had played live, Prince and his band started playing behind a scrim on the stage at 2:25 a.m.

“Musicology” came first and then Prince, wearing a stocking cap and a long-sleeve T-shirt, called out for “Cool,” the hit he wrote for the Time. In mid-song, the band shifted into Michael Jackson’s “Don’t Stop Till You Get Enough” and then the bandleader called out “Stevie Wonder,” which was a cue for the four NPG Horns guys to play the horn riff from Wonder’s “Sir Duke.” Prince mentioned that Wonder was recently in town.

“Housequake” was the perfect choice to funk up the party for a crowd that had dwindled to maybe 100 or so. Prince called on various band members to take solos and eventually called the next song, “Hot Thang.” He asked backup singer Liv Warfield to take some lead vocals.

“Can we do something from the ‘80s?” Prince then asked. “Are there any millennials in the house?” When no one responded (even though there were some in attendance), Prince, without missing a beat, said, “Just old people like me.” He then shifted into 1981’s “Controversy,” telling his staff to turn off the lights and the faithful to close their eyes and imagine they were in 1982. “What did you smell like back then?”

“People call me rude," he sang. "I wish there were no rules.” But at Paisley Park, Prince makes the rules. After playing the melody line from “Party Up” at the end of “Controversy,” he said the party was over.

At 3:10 a.m., before any fans could head to the exit, Prince ran out of the soundstage like a gleeful little kid with lights blinking in the heels of his shoes.