Some pop alliances make sense well in advance. Others make no sense even after the fact. Then there is the current collaboration between Nickel Creek, the sweet-tempered alternative bluegrass group, and Fiona Apple, the powerfully saturnine singer-songwriter.
Fiona Apple in Central Park on Tuesday, one of her tour dates with Nickel Creek.
Before embarking on a tour together two weeks ago the two parties seemed more or less incompatible. By the time they reached the Rumsey Playfield in Central Park on Tuesday night, the success of their pairing made it feel almost inevitable. While Ms. Apple leaned on Nickel Creek as her backing band, it might be just as fair to say she was a visiting dignitary in its world. And the band’s hospitality worked wonders; she seemed to be having an unusually good time.
Bright cheer comes with the territory for Nickel Creek, a longstanding trio of Chris Thile on mandolin, Sara Watkins on violin and Sean Watkins, her older brother, on guitar. The group formed before any of its members were teenagers, and harmonious precocity still guides its style. Even the recent announcement of a breakup landed playfully; no Nickel Creek fan could miss the parenthetical promise of its Farewell (For Now) Tour.
Over the last few years Nickel Creek has pushed increasingly toward songs that deal with another sort of breakup. The band’s 2005 album “Why Should the Fire Die?” (Sugar Hill) features songs that might, with less rustic instrumentation, serve the purposes of an emo band. A few of these got recognition applause on Tuesday; one had Mr. Watkins singing the phrase “I hope you find somebody more like you” in a passive-aggressive whine.
A newer song in this spirit by Mr. Thile was much more likable, perhaps because it was truer to the temperament of the band. It featured a catchy riff, a slippery melody and a mischievous refrain: “If you’re going to leave me/Set me up with one of your friends.” (Insert delighted cheer here; the lanky Mr. Thile gets a lot of these.)
Of course in Ms. Apple’s universe failed relationships are a more serious business. “What wasted unconditional love,” she sang during each refrain of “Oh Well,” sounding appropriately bitter. Strikingly, her self-recrimination wasn’t undermined in the slightest by Nickel Creek, operating as a four-piece with the addition of the bassist Mark Schatz.
Some of Ms. Apple’s songs, including the title track of her superb 2005 album “Extraordinary Machine” (Sony), actually sounded better in this setting. (Last summer on the same stage a more conventional band too often left her awash in melodrama.) On “Limp,” Ms. Watkins and Mr. Thile worked like a tag team, trading a mournful verse for a cathartic chorus. “A Mistake” was even better; its bluegrass reinvention outpaced the original.
Mr. Watkins, introducing the cabaret standard “I Walk a Little Faster,” noted that Nickel Creek had a history of casual meetings with Ms. Apple at Largo, a Los Angeles club. In that spirit they ventured some other covers, like “Walkin’ After Midnight” (Patsy Cline) and “I Want to Sing That Rock and Roll” (Gillian Welch and David Rawlings).
But the show worked best when Ms. Apple was singing her own arresting material, with Nickel Creek lending something more than strict support. There was no compromise in those moments, even as simmering resentment met good-natured fun.
