Fleetwood Mac's flexibility has always been its secret weapon, its three distinctive singers giving it a wide variety of sounds that few bands can match.

That becomes even clearer with the focus on singer/keyboardist Christine McVie at Madison Square Garden Monday night, marking her return to Fleetwood Mac after 17 years of retirement from the road.

With McVie back in the Mac, there is more of a balance of blues and rock. Her rich voice on "You Make Loving Fun" and "Everywhere" is a nice counterpoint to the more aggressive, rocking vocals of Lindsey Buckingham and the more ethereal singing of Stevie Nicks.

And when they all sing together, in the gorgeous "Rhiannon" or "Say You Love Me," it's still magical.

"I've been away for a long time," McVie told the cheering crowd. "You don't often get a chance to do what you love twice in your life."

It's still early in the tour, which launched last week, and they are still working out some pieces. (Fleetwood Mac returns to The Garden Tuesday night and plays Prudential Center on Saturday.) Nicks mistakenly tried to introduce "Over My Head," which was written by McVie, before laughing and yielding the stage, saying, "I don't know the story of this song."

However, the nervousness of such veteran performers just added to the charm of the night, which got stronger the deeper they got into the 2 1/2-hour set. Between Buckingham's epic guitar solos, Mick Fleetwood's massive drumming, John McVie's strong bass work, Nicks' patented spins to punctuate the lovely "Gypsy" and Christine McVie's lush vocals, Fleetwood Mac looked ready to take on what Buckingham has called "their next chapter."

SETLIST: The Chain / You Make Loving Fun / Dreams / Second Hand News / Rhiannon / Everywhere / I Know I'm Not Wrong / Tusk / Sisters of the Moon / Say You Love Me / Seven Wonders / Big Love / Landslide / Never Going Back Again / Over My Head / Gypsy / Little Lies / Gold Dust Woman / I'm So Afraid / Go Your Own Way // ENCORES: World Turning / Don't Stop / Silver Springs / Songbird