For the first time in their career, the Roots have nothing to prove.

No longer the scrappy underdog trying to add much needed depth to hip-hop, the Philadelphia collective have earned respect and have loaned their signature sound to artists of all varieties. But the great [and risky] thing about the Roots is that although they can now sit with the heavy-hitters, they still keep their seats at the outsiders’ table warm.

The artists on the Roots Picnic bill, including Santogold [a disappointing no-show], Sharon Jones and the Dap-Kings and noise-rock band Deerhoof, were all little-known indie acts with segmented fan bases. Without any other big name acts — except Gnarls Barkley who are still scratching their heads at their meteoric rise — The Roots packed the Festival Pier at Penn’s Landing Saturday proving their stance as music tastemakers.

DJ Jazzy Jeff gave a true Philadelphia welcome, spinning every hip-hop classic imaginable from coast to coast [giving extended play to the city’s own] and mixing in his trademark scratch techniques. The early birds who rotated between an air-conditioned, carnival-sized tent and the sun’s chokehold were dumbfounded when the Roots set up and performed less than two hours after the doors opened.

Frontman Black Thought opened with songs from the groups’ early albums, yet all eyes were on amiable drummer ?uestlove [the only drummer whose fame eclipses that of the leading man].

Jazz prodigy Esperanza Spalding, 23, turned what could have been a dull interlude into a finger snapping lounge session. The charming jazz vocalist plucked the strings of her acoustic bass with such deft the audience forgot the instrument was the size of a giraffe and two times her slim frame.

Guest drummer ?uestlove gave the electro-funk-soul group J*Davey, a much needed credibility boost. It took a few songs to adjust to the California duo’s Prince/new wave hybrid sound and lead female singer Jack Davey’s spastic movements, but they walked away with some converts.

Chicago rap duo The Cool Kids made the mistake of popping on stage without an introduction. One minute the crowd was shooting in and out of water hoses, then they looked up to see two guys dressed in Crayon colors trading rhymes. After the group zipped through tracks from their struggling sophomore album, they won over the crowd with their rendition of the Jazzy Jeff/Fresh Prince classic, “Summertime.”

Picking up the energy, Black Thought showed up in rare form going into a James Brown impression, channeling the soul man in song and dance. Yes, the rapper known for his heavy swagger found his good foot and singing voice in a wildly entertaining set, leaving his band members bent over in laughter.

Keeping the old school vibe, the basement funk band the Dap-Kings hyped the crowd for lead singer Sharon Jones, only to find the mic cut off when the vigorous singer yanked it from the stand. The well-oiled Dap-Kings went midway through their first song with Jones’ voice barely heard past the front rows. Not missing a beat, Jones gave a commanding performance and belted roaring codas that brought chills.

The Roots took the stage for their last appearance starting off with songs from their latest release, going down the list of fan favorites and squeezing in a game of “Name That Tune” hip-hop edition.

Even though the set was a non-stop adrenaline rush, every now and then fans would bend their necks toward backstage to see who might join the band on stage. Where was Chrisette Michele for “Rising Up,” Erykah Badu for “You Got Me,” Common, Mos Def? Some even asked about original Roots members Dice Raw and Rahzel, the human beatbox. Still, the Roots were more than filling without the Dave Chapelle Block Party guest appearances.

By the time co-headliner Gnarls Barkley appeared, many fans had left, most were hung over and the rest were dizzy from heat exhaustion. Some loyalists remained and were treated to an average Gnarls showing with small talk from a surprisingly mild Cee-Lo.

Unfortunately, after the Roots and a one-hour lull in between, Gnarls found themselves performing for a crowd who would have been content with an extended version of “Crazy” as the last call selection.