At Rogers Arena on Friday, June 3

I just discovered that I know way more Bruno Mars songs than I thought I did. For a guy with just one album and an EP to his name, the Hawaiian-born performer is surprisingly ubiquitous. He has his own hits, of course, but Mars may be equally well-known for his popping up damn near everywhere else. He has co-writing credits on everything from K’naan’s “Wavin’ Flag” to Cee Lo Green’s “Fuck You!” to Travie McCoy’s “Billionaire”.

He played that last one Friday night at Rogers Arena, after a somewhat awkward segue out of the old Barrett Strong number “Money (That’s What I Want)”, which allowed Mars to rip into some Chuck Berry-esque licks on his seafoam-green Stratocaster. Mars isn’t a rock ’n’ roller, really, although he kind of dresses like one. In his sawed-off denim jacket and black biker T-shirt, with a red bandana hanging out of one of the back pockets of his jeans, he looked like a guy who has been taking fashion advice from Bruce Springsteen, although the fedora puts his own spin on the blue-collar look.

If he’s not a rocker, though, what exactly is Mars? He’s a bit like a human jukebox, in that his songs don’t all sound like they’re by the same artist. “The Lazy Song” and “Count on Me” might come across as the products of a songwriting circle attended by Jack Johnson and Jason Mraz, but “Our First Time” is a slightly icky, break-out-the-baby-oil soul-pop ballad, and “Liquor Store Blues” is straight-outta-Kingston reggae.

What his material lacks in consistency, though, it makes up for in hooks. It’s downright uncanny that so many of these songs sound like they've been around forever, even though most of them came out a mere eight months ago on Mars’s debut album, Doo-Wops & Hooligans. Sounding time-tested is a pretty good trick for a 25-year-old.

Mars’s coheadliner Janelle Monáe, whose set preceded his, is the same age. Unlike Mars, though, she doesn’t so much switch styles from song to song as mash every conceivable genre together in the course of a single number. The pompadour-sporting performer’s music isn't easy to describe if you've never heard it. It's often fast and driving without being rock; it’s slick and tuneful and infectiously energetic but lacks the sort of hit-you-over-the-head hooks that would make it a truly mainstream pop confection. The percussion and chord changes often bear hints of Afro-Cuban jazz, but those elements never overpower the distinctly American brand of vintage soul that informs many of the songs.

With Monáe and her band attired simply but strikingly in coordinated black-and-white outfits, the set was long on style but short on theatrics. Well, there was the business with the menacing black-robed figures whom the singer dispatched with a wave of her fingers. Oh, and the bit where she took to an easel at centre stage and painted a butt. No word of a lie: it was a human butt, with the word "LOVE" written under it. I'm not sure what the message is there, and I'm not going to speculate, because to be honest I couldn't do so in good taste.

As she ably demonstrated on a stripped-bare version of Charlie Chaplin's "Smile", on which she was accompanied by a single electric guitar, Monáe has a decent set of pipes and a way with carefully controlled melisma that makes up for the fact that her tonal range is somewhat less than operatic. In other words, Mariah Carey she ain't—and thank God for that.

Her performance style is less about vocal fireworks and more about sheer energy, in any case. During a spell-binding, set-closing version of “Come Alive (The War of the Roses)”, Monáe brought her band down to a whisper-soft level, with everyone lying down on the stage, before ramping the energy back up with a shriek and a toss of her now-dishevelled mane. Then she went down onto the floor and through the middle of the crowd, and after that I lost sight of her. But she’ll be back.