TAMPA — It has been nearly 40 years since the classic lineup of Fleetwood Mac first performed together. The band has been in existence even longer, but when most people think of “Fleetwood Mac” they think of eccentric guitarist Lindsey Buckingham, mystical songstress Stevie Nicks, crazed drummer Mick Fleetwood, quiet bassist John McVie and down-to-earth keyboardist Christine McVie. Four decades is a long time for any group of people to stay together, and members of the notoriously combustible Fleetwood Mac, not surprisingly, have spent much of that time in and out of the group. The past couple of tours and the last album, with everyone but Christine McVie, was the closest many thought there would be to a reunion. McVie’s full-time return is enough to celebrate a tour — there’s no new album to promote — and on Saturday night at Amalie Arena fans were ready to welcome her back, giving McVie her own ovation. Unsurprisingly, the set list leaned heavily on “Rumours,” still one of the biggest-selling albums of all time. Starting with a thundering “The Chain,” the band defied age and its reputation as a soft rock band. The biggest surprises were songs from “Tusk,” the follow-up to Rumours considered by some to be a flop. The songs aren’t as familiar, but the band seemed to enjoy playing them and stretching out “I Know I’m not Wrong” and “Sisters of the Moon,” and reinventing “Tusk” as a blues guitar workout. Buckingham stalked the stage as if possessed. His solo run through “Big Love” and his guitar work on “I’m So Afraid” drew wild cheers from the crowd.