Pete Townshend was jigging joyfully around the stage of the Amphitheatre, and at one point he went up to Roger Daltrey and hugged him.

John Entwistle was smiling a lot, and even broke his usual silence between numbers to mutter in the microphone for Roger to can it (not his words) during a particularly lengthy explanation of a song in “Quadrophenia.” Keith Moon was flailing away with his mouth open as if surprised that his energy was limitless.

The four members of the Who were delighted, and for good reason. Thursday night’s concert was one of the finest they have ever performed. Somehow everything fell together perfectly — all the music, the showmanship, the feeling, the fun of rock and roll.

All this in the face of an environment that was anything but conducive to such a fine performance. In fact, unless you were among the squirming masses in front of the stage or in the first few rows, you probably didn’t scream too much, except at the people standing on their chairs and blocking your view. And if you weren’t close up on the main floor, chances are you were zapped by the Amphitheatre’s patented double and triple echoes.

But that didn’t affect the Who, thank goodness, and the lucky few who survived the shoving and squashing and rain of projectiles thrown by disgruntled folks in the rear could lose themselves totally in the Who’s magic.

The set started with four oldies — “I Can’t Explain,” “Summertime Blues,” “My Wife” and “My Generation.” Entwistle stepped into the lead singing role for “My Wife,” which he wrote, and it worked fine. John is flexing his weight as a singer more now, from the harmonies of “The Punk Meets the Godfather” to the trading leads in “Helpless Dancer.”

The “Quadrophenia” segment was jabbed and jostled by Pete to deflate its seriousness, but that was in between the numbers. The actual performance was straightforward and powerful, and the audience roared its approval at the end.

Then it was time for “Won’t Get Fooled Again,” the biggest crowd-pleaser, and “Pinball Wizard” and “See Me, Feel Me” from “Tommy.” Daltrey sang magnificently throughout the set, but most amazing was how he could still make this last number as moving in its umpteenth performance as it was in the beginning.

Townshend was at his most acrobatic and playful, while playing his hard, rhythmic guitar style with zest and power. Moon whipped his drums smoothly and forcefully and sang his part in “Bell Boy” in perfect off-key. And Entwistle was the stalwart at bass as usual, with fingers flying on both hands for his patented fluid foundation and those special lead parts.

Lynyrd Skynyrd opened the evening with some funky Southern guitar-rock and shook out a good response from the audience.