Sting and Peter Gabriel at Nationwide Arena

Sting described his collaborative Rock Paper Scissors tour with Peter Gabriel, which kicked off at a packed Nationwide Arena on Tuesday, as an "organic battle of the bands," suggesting the two assembled the set list as casually as old friends spinning records in a basement rec room. The pair took turns playing songs and then "responded to each other's choices," he said.

It's not unusual for stars to pair up for a tour that lets them play for a larger audience than a solo jaunt might allow (see Drake and Future tag teaming Nationwide in August). But rarely do established artists intermingle as joyously as the Sting/Gabriel mutual admiration society, which shared everything from an armada of backing musicians to actual material. When percolating synthesizers announced the arrival of Gabriel's "Shock the Monkey," for one, it was the reedy-voiced Sting who handled lead vocals. Later, Gabriel returned the favor, digging deep into his compatriot's catalog for a bluesy "If You Love Somebody Set Them Free."

Despite sharing an obvious kinship and similar backgrounds - both were born in England just a couple years apart (at 66, southeastern-born Gabriel has two years on 64-year-old northerner Sting) and both have taken to exploring global sounds over the course of their decades-spanning careers - the concert often highlighted pronounced differences between the two musicians, who previously toured together in the 1980s in support of Amnesty International.

In general, Gabriel staked out artier terrain, traversing foreboding, machine-like rhythms on the aptly titled "Darkness" and turning out a doom-laden "The Rhythm of the Heat" that could have soundtracked a musical version of Dante's descent into Hades. Sting, in contrast, tended to revel in the populist role, following the latter with a soaring version of "If I Ever Lose My Faith in You" that cut the overcast skies with the force of the high noon sun.

The trend repeated itself as the concert drew to a close, with Sting falling back on time-tested fan favorites ("Roxanne," "Every Little Thing She Does Is Magic," "Every Breath You Take") as Gabriel interspersed hits like "Solsbury Hill" and "In Your Eyes" with more unexpected fare like "Love Can Heal," a tender ballad he offered in tribute to British legislator Jo Cox, who was assassinated by a gun- and knife-wielding attacker earlier this month.

Similar bruising revealed itself on Sting's "Fragile," which the musician dedicated to the victims of the mass shooting at Pulse nightclub in Orlando, citing a need to embrace empathy and solidarity in the face of hatred and violence. The tune arrived in the middle of a three-song suite that unfolded like a commentary on these horrific events, beginning with Sting's "Driven to Tears" ("What is my reaction? What should it be? Confronted by this latest atrocity," he cried) and closing with Gabriel's "Red Rain," in which the narrator appeared to be trapped in a nightmare he or she couldn't escape. "I can't watch anymore," Gabriel crooned, a feeling shared by many inundated with cable news updates over the last week.

At times, Gabriel's presence appeared to loosen up Sting, who interrupted "Roxanne" with a verse from Bill Withers' "Ain't No Sunshine" and paid tribute to his dueling partner by kicking off "Message in a Bottle" with a Celtic-tinged verse from Genesis' "Dancing with the Moonlit Knight."

Sting further flashed this playful side in the abrubt transition between his own "Walking in Your Footsteps" and Gabriel's "Kiss That Frog."

"They say the meek shall inherit the world," he sang at the close of the pastoral, introspective "Walking…" He then launched immediately into the strutting, cocksure riff from "Frog," a move that suggested he wanted no part of that earthly inheritance.

Set List

"The Rhythm of the Heat"

"If I Ever Lose My Faith in You"

"No Self Control"

"Invisible Sun"

"Games Without Frontiers"

"Shock the Monkey"

"Secret World"

"Driven to Tears"

"Fragile"

"Red Rain"

"Dancing with the Moonlit Knight" into "Message in a Bottle"

"Darkness"

"Walking in Your Footsteps"

"Kiss That Frog"

"Don't Give Up"

"The Hounds of Winter"

"Big Time"

"Englishman in New York"

"Solsbury Hill"

"Every Little Thing She Does Is Magic"

"If You Love Somebody Set Them Free"

"Roxanne"

"Love Can Heal"

"Desert Rose"

"In Your Eyes"

Encore

"Every Breath You Take"

"Sledgehammer"