Sylvan Esso owes its existence to Milwaukee's Cactus Club. It repaid the favor with a sweaty surprise show.

Tuesday night at the Cactus Club in Milwaukee, Sylvan Esso took it back to the beginning.

Well, technically, back to before the beginning.

In 2010, Nick Sanborn — a onetime Cactus Club employee who was in local bands Decibully and Collections of Colonies of Bees — was booked to play a gig at the Bay View music venue with his electronic project Made of Oak.

Also on that bill was Mountain Man, a folk trio from Vermont featuring Amelia Meath. Sanborn and Meath met and became friends that night. Three years later, they formed electro-pop duo Sylvan Esso. Three years after that, in 2016, they married each other.

And in less than a decade’s time, they’ve released four albums, been nominated for two Grammys, performed all over the world, and become popular enough to launch their own label.

So on Monday morning — on a break from opening arenas and amphitheaters for Odesza, and a day after throwing the first pitches at a Brewers game — Sylvan Esso announced a surprise show for Tuesday night at Cactus Club. Tickets went on sale immediately; the show sold out in three minutes.

If it seemed too good to be true, that a band big enough to headline festivals and larger theaters and ballrooms was playing for fewer than 200 people in a Milwaukee club, there were fleeting moments where that threatened to be the case.

Just five songs into their 78-minute set, Sanborn's laptop overheated in the packed, sweltering room, forcing Meath to bust out some jokes about lobsters and whales (including some "whale talk") and lead a "Happy Birthday" singalong for an audience member. Five songs after that, just as the fluttering opening notes of breakout single "Coffee" filled the room, there were again technical issues.

And shortly before that second unplanned pause, Sanborn seemed almost apologetic, suggesting they were "really loose," likening the crowd to "guinea pigs," as they played some songs from last month's superb album "No Rules Sandy" live for the first time. (Ultimately, eight of the 17 songs on Tuesday's setlist were from "No Rules Sandy.")

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Nevertheless, the crowd, despite the heat and snafus, was elated, soaking in this rare treat of an intimate show.

And when the band overcame the technical issues and powered through "Coffee," with no further problems occurring after that, there was a clear energy surge in the small room. "Numb" was especially electrifying after "Coffee," with Meath literally dancing away the ennui all across the stage over Sanborn's skittering, shimmering beats as glitchy projections filled the stage.

"This is a real show now," Sanborn said soon after.

Sanborn and Meath are such seasoned performers with such strong chemistry that they had already demonstrated plenty of star power up to that point.

But Sylvan Esso's greatest strength is their determination to defy expectations.

Meath has a dynamic vocal range, and could opt for roof-blasting belting if she wanted. That's generally not her MO; often Tuesday night, she sang a few clicks above a stage whisper, trusting that the richness of her voice even at a lower volume, and the confessional, sometimes mysterious nature of her vocals, would draw people in.

So when she busted out those dance moves — never too polished, always seemingly spontaneous — or her voice did briefly soar, like for the tender embrace of living for "Die Young" or after a chilling, volume-dropping moment of "No Rules Sandy" song "Sunburn," the effect was all the more striking.

And as a producer, Sanborn has the skill to sweep people away with seismic beats. But he also avoids the big strokes and predictable patterns used all too frequently by EDM stars. His soundscape is incredibly intricate, and in turn intimate, like the woodpecker-like cadence and soft rattle of "Coffee."

At Cactus Club, Sanborn threw several thrilling curveballs that differed from the recordings — sprinkling in the sounds of bottle percussion, cowbell and snare drum brushing for "Die Young"; embracing Afrobeat rhythms for crisp "No Rules Sandy" song "Cloud Walker"; souring a note for a tangy double-take during the rev-up for "Radio"; delaying the bass drop to an unexpected moment for "No Rules Sandy" standout "Echo Party."

But it all still got people dancing Tuesday, and Sanborn himself was dancing exuberantly through the show.

As much fun as the crowd was having, it was clear Meath and Sanborn were enjoying it even more. Near the concert's end, Sanborn took a moment to take in his blessings, reflecting on working at the club and giving a shout-out to the person who booked that fateful show with Meath in 2010. If that hadn't happened, there would have been no Sylvan Esso, and they wouldn't be married.

And then for the night's final number, Sylvan Esso brought out their friend Chris Rosenau of Collections of Colonies of Bees, and together the trio did a song they very rarely play live, their joint cover of Califone's sublime "Funeral Singers."

At that moment, this no longer was a show. It was a blissful, powerful homecoming.

Five takeaways from the Cactus Club show

• There was another purpose to Tuesday's show besides the homecoming. Proceeds benefited the Midwest Action Alliance, one of several organizations helping with abortion services the duo have been doing fundraisers for, Sanborn said Tuesday.

• Even when the show ended, Sylvan Esso didn't go anywhere. Sanborn stuck around to do a DJ set in the bar.

• Sylvan Esso may have close ties to Cactus Club, but the booking coup was truly a testament to the 26-year-old venue's revered reputation. (Jack White also gave the tiny Bay View club a shout-out in Milwaukee last month.) When the pandemic hit, Cactus Club, with Kelsey Kaufmann taking over as owner just a month prior, was arguably Milwaukee's most vulnerable venue. It not only survived, but in terms of its bookings, it's thriving.

• As cool as it was to see Sylvan Esso in such an intimate setting, naturally not every Milwaukee fan could get in, and they're overdue for a bigger show in the city. Fingers crossed we'll see them play the Eagles Ballroom, Riverside Theater, Miller High Life Theatre, BMO Harris Pavilion or Summerfest in 2023.

• You won't have to wait that long to see Meath in Milwaukee. She's performing with her new band the A's with fellow Mountain Man member Alexandra Sauser-Monnig at the Pabst Theater Oct. 20, as the opening act for Marcus Mumford.

Sylvan Esso's Cactus Club setlist

1. "Moving"

2. "Ferris Wheel"

3. "Train"

4. "Dress"

5. "Alarm"

6. "Die Young"

7. "Cloud Walker"

8. "Your Reality"

9. "Look at Me"

10. "Coffee"

11. "Numb"

12. "Didn't Care"

13. "Sunburn"

14. "Radio"

15. "Echo Party"

16. "Rewind"

17. "Funeral Singers" (Califone cover, with Chris Rosenau of Collections of Colonies of Bees)

Contact Piet at (414) 223-5162 or plevy@journalsentinel.com. Follow him on Twitter at @pietlevy or Facebook at facebook.com/PietLevyMJS.

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This article originally appeared on Milwaukee Journal Sentinel: Sylvan Esso returns to its roots with surprise show at Milwaukee club