Sting was flummoxed.

Part way through his performance of “The Hounds of Winter” on Sunday night at Xcel Energy Center, his microphone and the entire sound system went all statick-y. Loud, cover-your-ears statick-y. He had to abort the song and leave the stage 90 minutes into his joint concert with Paul Simon.

Two minutes later, Sting and his band returned and essayed “Roxanne,” his breakthrough hit with the Police. But his vocal microphone was dead and the crowd of 7,000 took over the vocal duties for the entire song. Karaoke with Sting’s band — for $252 for the top ticket. Embarrassed, he walked off the stage.

Wait, isn’t this the Xcel Energy Center? Was this the revenge of Simon’s once-and-future-partner Art Garfunkel (whose in-laws live in the Twin Cities)? Was it time to sing “Sounds of Silence” or “Bridge Over Troubled Water”?

The ever-resourceful crowd broke into a spontaneous “sending out an SOS,” echoing the words Sting had sung moments earlier in the Police’s “Message in a Bottle.”

Meanwhile, Sting decided to grab a cup of tea — a Brit’s first move when trying to resolve a crisis — while the sound engineers tried to fixed things. But to the rescue came Simon. A guy who knows how to perform with just a voice and guitar, he arrived onstage, summoned Sting (tea cup and all) and the two of them stood at Simon’s microphone (which was working just fine) and harmonized on the Everly Brothers’ “When Will I Be Loved.”

They certainly looked like an odd couple: Simon and Sting, separated by 10 years of age, 9 inches of height and two or three levels in the pantheon of popular music. And yet, besides being longtime residents of the same New York City building and inductees in the Rock and Roll Hall of Fame, the two pop stars have other things in common. Whether in a group or solo, their music has been characterized by ambition, erudition and sophistication. And they both work better with collaborators.

With the Police retired and Simon & Garfunkel in moth balls, it was neither expected nor surprising that these two veterans teamed up for the 19-city On Stage Together Tour. Despite the sound problems, their two-hour, 35-minute show Sunday was as nourishing as it was nostalgic. This pairing was certainly more successful than tours Simon has done with Bob Dylan (1999) and Brian Wilson (2001), even though, on paper, the Simon-Sting hookup didn’t make much sense beyond their shared love of reggae and world-music rhythms.

With Simon and Sting working in an alone-and-together format Sunday, the show recalled the many tours that Elton John and Billy Joel have done together in recent years.

Backed by their merged bands, Simon, 72, and Sting, 62, started as a duo, swapping verses on Sting’s “Brand New Day,” then Sting singing counterpoint on Simon’s “Boy in the Bubble” and Sting using his mid-range while Simon took the high part on Sting’s “Fields of Gold.” It certainly wasn’t the gorgeous, rooted-in-childhood vocal marriage of Simon & Garfunkel, but these neighbors found a way to make the blend work.

At times, they creatively flipped things around, with Simon taking most of the lead vocals on Sting’s “Fragile” and Sting doing a solo acoustic version of Simon’s “America.”

The solo sets demonstrated their ambitiousness coupled with the kind of restlessness that prompts them to reimagine their old favorites. Simon took the fans to “Graceland” with a chugga-chugga train-evoking guitar undercurrent. Sting seasoned “Englishman in New York” with both reggae and jazz.

Since Sting’s second solo segment was curtailed, Simon’s solo efforts, in the end, seemed more rewarding. “50 Ways To Leave Your Lover” was jaunty and jazzy, the lesser known “Dazzling Blue” was pretty in its minimalism, “Still Crazy After All These Years” found Simon at his most passionate vocally, and “Diamonds on the Soles of Her Shoes” started with stunning a cappella harmonies before turning into a big party.

Sting regained his composure and prominence in the closing duets: “Bridge Over Troubled Water,” “Late in the Evening” and, on “The Boxer,” with just the two singers, Simon’s acoustic guitar and no backup musicians. Simon apologized that his songs were dominating but he explained that there were sound problems with Sting’s equipment.

By the end of the evening, all seemed good. Then, as they took a bow, Simon’s guitar started feeding back. Sting took a step back. Then came the sound of silence — and roaring applause.