I truly hope someone warned Rod Stewart. Seriously. Did anyone tell him just exactly who he had opening for him on Saturday at First Niagara Center? It almost seemed cruel, having “Rod the Mod” follow Santana, a band that changed the course of popular music while Stewart was getting busy going soft.

And yet, somehow, Stewart pulled it off.

His show – Las Vegas glitz and all – came across as a particularly awesome visit with your favorite uncle, over a pint or three, with the same old stories being trotted out to the same old effect once again, and you thinking to yourself, “Yes, sometimes life is just plain nice.”

Pairing Stewart with Santana was a weird decision from the outset, and Saturday’s show did not transform that incredulity into an “a-ha!” moment at all. Rather, it underscored the ill match. Santana played first, and offered a scorching set of Latin-jazz-rock-pop-R&B-funk fusion that was very much in keeping with the best work of this band during its best decade, the ’70s. Stewart followed by opening up with “Infatuation,” a flaccid but fun entry in his rather dubious 1980s canon. So, you see, no one arrived planning on accommodating the other. What you got was Santana’s peanut butter forcefully intermingled with Stewart’s chocolate. It didn’t really end up working, taste-wise, but what the hell? It was an awfully good time.

Santana played first – a mistake if you’re Rod Stewart, or pretty much anyone else save the Allman Brothers Band or Phish. Why? Really? You had to ask? Um, because this band remains one of the most ferocious jam-bands going, on a good night. And Saturday was a good night.

Opening with the sun-soaked Latin groove of “(Da le) Yaleo,” and moving straight into the new Spanish-language pop hit “La Flaca,” the Santana band did what it has been doing for decades, but it certainly did it with more persistence of vision than this writer has seen the band summon over the past five years. (A time period during which I’ve seen Santana four times.) Yes. Carlos and company simply burned.

Keyboardist David Matthews – no, not that one – tore up a blistering jazz-based piano solo during “La Flaca,” and Santana kept his eyes on him the whole time, apparently as a way to let his bandmate know that he planned on doing everything within his power to blow him out of the water. He came close, with his own solo.

The hits came, as we knew they would, in the form of “Black Magic Woman/Gypsy Queen,” “Oye Como Va,” “Maria Maria” and “Evil Ways.” The crowd – tepid at first, as if they didn’t know who Santana was, and had come solely to see Stewart do his well-rehearsed thing – erupted about 30 minutes into the set, as the women down front finally gave in to the music’s invitation to dance, and the dudes responded to the sway in the hips all around them. Magic.

Santana’s wife, the jazz/rock/fusion drummer Cindy Blackman Santana, joined the group for a torrid “Corazon Espinado,” and then stayed for a drum solo that was absurdly virtuosic and impeccably grooving, by which point I was muttering to myself, “Rod who?”

The pop-Latin hit “Smooth” and a sultry “Soul Sactrifice” followed, and we all could’ve left then, satisfied and satiated.

Ah, but Sir Roderick was to follow. And he did exactly what he has always done. He charmed female and male alike with his “mate down at the pub” persona and his eminently soulful – if less dynamic in range, following throat surgery several years back – singing.

Rod played a “hits” show on a stage that looked like the set from Robert Palmer’s MTV ‘80s mainstay video “Addicted to Love.” It was horribly cheesy, and yet, somehow so proper. He played his best-known tunes, with only a slight emphasis on his more respected rock and R&B and soul years.

Sam Cooke’s “Twistin’ the Night Away” was an obvious choice, and Stewart chose it; The Persuaders’ “Some Guys Have All the Luck” was far too treacly for the gig, and Stewart chose that one, too, and delivered it as if Saturday’s show was his own personal Las Vegas Casino gig; “You Wear It Well” was the kind of song we wanted more of and didn’t get enough of on Saturday, but Stewart poured his heart into it.

Santana strolled onto the stage for the set’s highlight – a stirring take on “I’d Rather Go Blind,” a song associated with blues great Etta James. This piece sounded an awful lot like Stewart’s “People Get Ready,” for which he reunited with old bandmate Jeff Beck, with transcendent results.

Man. What a performer. Still.

These two have about as much in common as do Barbra Streisand and Lady Gaga, but Saturday’s show didn’t need rational thought to prop it up. Incredibly, it worked. We were granted a super-strong Santana show and an average – for “average,” read “sturdy, and fun” – Stewart show. And for a few magic minutes, the two married their respective talents into a soulful union. I’ve got no complaints.