At long last, the time for the Wilco and Sleater-Kinney “It’s Time” tour to play the Mann Center arrived on Sunday.

The pairing of the two born-in-the-1990s rock bands with divergent artistic approaches but similarly open-minded fan bases was supposed to be one of the most intriguing shows of the summer of 2020.

The coronavirus shutdown prevented that from happening, and the new date — with the addition of Chicago singer and rapper Nnamdi — coincided with large gathering anxieties rising with the increase in COVID cases due to the highly transmissible delta variant.

Live music again being at risk, just as it makes its return, gave the sticky summer night at the Fairmount Park amphitheater a heightened atmosphere among bands and fans grateful to be back doing what they loved.

The sense that it could all be taken away again — underscored by Henri that nearly did in the show in New York the night before, and the broken wrist that caused Nnamdi to miss the tour’s first show — contributed to the acts coming through with energetic happy-to-be-on-stage-again performances.

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The show was the first at the Mann to require proof of vaccination or a negative COVID test for entry, a policy instituted at the insistence of the bands, that will become mandatory at all shows by promoter Live Nation starting Oct. 4.

The process was orderly, with ticket holders asked to mask up in four swift moving lines outside the gates. Free masks were handed out to anyone without one upon entry and the crowd obeyed the venue’s mandate to wear a face covering when moving about the venue, though many removed them at their seats.

Wilco began their headlining set with a pertinent opener: “A Shot In the Arm,” from the Chicago band’s 1999 album Summerteeth. The brisk, bracing rocker is a broken love song that was surely selected for its accidental pro-vax messaging. “Maybe all I need is a shot in the arm,” Jeff Tweedy sang.

But it also includes another lyric that speaks to the exploratory spirit that has continued to guide the band, even as the sextet has settled into a comfortable space as purveyors of what fans fondly refer to as “Dad rock.”

“What you once were isn’t what you want to be anymore,” Tweedy sang, and could have been referring to the artistic restlessness that has led to the many stages of Wilco that were visited upon over the course of a genial 90-minute set.

There was roots-rock Wilco with “Box Full Of Letters,” from 1994′s A.M. and glitchy, art-rock Wilco with “I Am Trying To Break Your Heart” from 2001′s Yankee Hotel Foxtrot; jam-band Wilco, with avant guitarist Nels Cline’s majestic solo on “Impossible Germany” from 2007′s Sky Blue Sky; and nervous indie pop Wilco on “Love Is Everywhere (Beware),” from 2019′s Ode To Joy.

Tweedy kept busy during the shutdown. His nightly The Tweedy Show virtual couch sessions featuring his sons Spencer and Sammy (shot by his wife, Sue) were spirit sustaining.

But it didn’t fill the gap left by live performance. “Did you all miss this thing?” he asked. “Not just us. But this. It feels like an honor to get to play for you, especially for everybody for who it’s their first time out.”

Sleater-Kinney also kept busy while live shows were off the books. The riot-grrl era Pacific Northwesterners who became the duo of singer guitarists Corin Tucker and Carrie Brownstein after drummer Janet Weiss left in 2019 recorded their new Path of Wellness last summer while their home base of Portland, Ore., was a battleground between protesters and police.

That season of strife was chronicled in both “Shadow Town” and “Down The Line,” two highlights of the band’s amped up hour-long set, with the latter turning on an all-too-true lyric that also fit the fraught return-to-concerts moment music fans are angsting through. “It’s not the summer we were promised,” Brownstein sang. “It’s the summer we deserve.”

Sleater-Kinney still retain their defining characteristics: Brownstein’s ripping, grabby guitar riffs and leg kicks that subvert and reclaim male guitar hero dude stage moves and Tucker’s five-alarm-the-world-is-on-fire banshee wail.

But as they move forward from the disappointment of 2019′s St. Vincent-produced keyboard-heavy The Center Won’t Hold with the thankfully more guitar-centric Path Of Wellness they are transformed as a band.

Instead of the unconventional — no bass player — power trio they were with Weiss, S-K is now a six piece, with three dudes in the back on bass, drums, and keys. Brownstein and Tucker were joined on guitar by She Shreds magazine founder Fabi Reyna, who got her share of solos in, lighting up “Modern Girl” in particular.

During the set which pulled almost exclusively from albums recorded since 2005′s The Woods, all but ignoring the band’s first six records, Brownstein coaxed ardent fans to move up and gather at the stage.

After closing with the roaring “Entertain” from The Woods, she said, “Music is about being together again, so thank you for being together, thank you to the security for letting our fans up here, and thank you for dancing. Stay healthy.”

Nnamdi was unable to play guitar due to his broken wrist, but that didn’t diminish the effectiveness of his all-too-brief opening set.

The songwriter and bandleader — whose last name is Ogbonnaya — makes captivating out-of-left field art-pop and has a broad vocal range which he employs with precision, sometimes using pitch altering Auto-Tune but mainly dazzling all on his own. No disrespect to the headliners, but of the recent works by the three acts on the “It’s Time” bill, it’s his album Brat that captures an artist on a creative upswing.