I always assumed that Justin Bieber was a smart guy. Now I have proof.

I've been getting a kick out of reading all these news reports about the teen idol attending his first phish show, earlier this week in Southern California. Sounds like young Bieber had a blast. And why wouldn't he? Phish rocks -- just ask "phans" in the Bay Area

The Vermont quartet -- consisting of vocalist-guitarist Trey Anastasio, drummer Jon Fishman, keyboardist Page McConnell and bassist Mike Gordon -- certainly delighted its local followers on Saturday at the Bill Graham Civic Auditorium in San Francisco.

The show -- the second part of a three-night stand at the venue -- wasn't quite as good as what was witnessed on Friday (and, hopefully, the best is still yet to come on Sunday). The band was somewhat cold at the start, motoring along on autopilot through a surprisingly uneven first set, but really blazed during the nightcap.

One of the many things I dig about Phish is that you never know what songs will turn out to be highlights on any given night. That's vastly different from, say, at a Rolling Stones concert, where you can basically bet the farm that "Sympathy for the Devil" and "You Can't Always Get What You Want" will be much better than anything played from the '90s. With a jam band like Phish, however, any song in the set list can turn out to be a stunner.

Traditionally speaking, I'm not a big fan of either "Wolfman's Brother" or "Ocelot" — two songs that can often be little more than filler on a Phish set list. On Saturday, however, the band really clicked on those two numbers -- and they turned out to be highlights of the first set.

Conversely, some of the band's usually dependable cuts -- like "Maze" and "Split Open and Melt" -- sounded somewhat pedestrian during this show. All was forgiven when Phish closed the first set with a tremendously fun and tight version of "Cavern."

The second set was much better. Much, much better. Indeed, the second set was downright epic -- beginning with a thrilling version of TV on the Radio's "Golden Age" (which is currently one of the best offerings in Phish's ample cover-song book.)

The foursome then ran through a number of its "greatest hits." (I use quotation marks because, well, Phish doesn't really have greatest hits -- just longtime fan favorites.) The players sounded strong as they jammed from "Piper" into "Mike's Song" into "Simple."

Phish then took a break for a concise spin through its radio-friendly pop-rock nugget, "Backwards Down the Number Line," before heading back into lava-lamp land as it blended "Carini" into "Wilson" into "Weekapaug Groove."

Awesome second set, gentlemen. Bieber would've loved it. Looking forward to more on Sunday.

Here's the setlist from Saturday:

"Runaway Jim"

"Wolfman's Brother"

"Nellie Kane"

"Beauty of a Broken Heart"

"Ocelot"

"Maze"

"I Didn't Know"

"46 Days"

"Tube"

"When the Circus Comes"

"Sugar Shack"

"Split Open and Melt"

"Cavern"

Set 2:

"Golden Age"

"Piper" >

"Mike's Song" >

"Simple"

"Backwards Down the Number Line"

"Carini" >

"Wilson" >

"Weekapaug Groove

"The Horse" >

"Silent in the Morning"

"2001"

"Fluffhead"

"Loving Cup"

Encore

"Show of Life"

"Character Zero"

Follow Jim Harrington at http://twitter.com/jimthecritic, www.facebook.com/jim.bayareanews and http://blogs.mercurynews.com/aei/category/concerts.