Despite being one of the most popular and most mainstream-geared genres in music, country can sometimes still be a pretty funny little universe all to itself.

If you're not a country fan and I give you the names Carrie Underwood and Keith Urban, and then ask you who's the bigger star, you'll choose the former without even blinking. But to millions of country loyalists, including the overwhelming majority of folks who packed the RBC Center on Saturday night, it's Urban who rules the roost.

It's no secret that good-looking male stars and bountifully appreciative female fans are two of pop-country's surest commodities. Such is the case with the hunky Urban, who may have yet to release a single that's cracked the top 20 on the Billboard pop charts, but who had no trouble whatsoever putting an estrogen-heavy crowd into hysterics.

So where did that leave "Idol"-conquering, cross-format chart-topper Underwood? Well, I've read other accounts of recent shows from the Keith-Carrie tour that seemed to find the young country queen wanting in her ability to work a crowd with the energy and aplomb of her Aussie tour-mate. Of course, it's far from Underwood's fault that she's sharing a bill with a piece of man-candy, and that consequently much of her audience would be made up of Urban-besotted ladies and their potentially eye-rolling boyfriends or husbands.

In fact, Underwood's opening set was the night's highlight. Not only is her material significantly stronger than Urban's, she also possesses a hint of genuine swagger that he's lacking, ably putting on sassy disinterest for "The More Boys I Meet" and tearing full-throated into an exhilarating cover of Guns N' Roses' "Paradise City."

For the vast majority of the time, however, Underwood is the smiling All-American girl who just happens to possess a hall of fame voice. Her songs play remarkably well to her strengths, their occasionally generic nature actually serving as a plus because of the awe-inspiring inclusiveness of her pipes. "I Know You Won't" was a genuine tour de force, and while it may have seemed incongruous for Underwood to be incessantly tossing little waves and smiles to the crowd even when she was in the guise of a seamier song like "Flat on the Floor" or "Last Name," it really made perfect sense. Underwood gladly absorbs all the foibles and vices of her audience, and then sends it back gift-wrapped as big-hearted, honest fun.

Urban was fun too, and he has a rapport with his crowd that feels more genuine than most, charmingly bringing a young girl on stage who'd brought an enormous poster with cutout holes for his and her heads, and also inviting the N.C. State drum line to perform some percussive feats between songs.

Still, Keith took significantly longer to really get cooking than did Carrie, starting well but then weighing down much of the middle of his set with undistinguished ballads, which aren't Urban's strong suit regardless of his sensitive reputation and the occasional stunner like "Tonight I Wanna Cry." More than possibly any other artist currently succeeding under the pop-country umbrella, Urban truly stretches the definition of what is and isn't country, considering how little of his music contains more than cursory amounts of the elements traditionally associated with the genre.

That's not a knock on Urban (Carrie Underwood's surely no Maybelle Carter herself), just an observation that he's essentially a pop-rock and adult-contemporary artist, one who's admittedly getting better, as the selections from his most recent album, 2006's "Love, Pain and the Whole Crazy Thing" (including "Stupid Boy," "Faster Car" and "I Told You So") provided many of the set's standout moments.

Urban's soap star good looks anticipate a kind of genial blandness on his part, but while I was tempted to write him off at first as a blank slate kind of stud, Urban ultimately worked hard enough and enthusiastically enough to prove himself a competent showman. Still, a healthy portion of his fanfare should've gone to the truly astounding, oddly underappreciated Ms. Underwood.