The Who, the thinking-man's rock band from Britain, presented a stunning two-hour and 15-minute concert yesterday afternoon that captivated an estimated 140,000 at JFK Stadium in Philadelphia.

It was the biggest rock show in the Northeast since last fall's Rolling Stones concert, also at JFK.

Although no major incidents were reported, the crush of the crowd — many of whom apparently used counterfeit tickets to get in — was nearly unbearable inside the stadium. The stadium has 92,000 seats. There were reportedly 50,000 counterfeit tickets circulating. People were also attempting to get in using tickets originally sold for the Who's cancelled Friday concert at JFK.

Set off by huge white, red-bordered letters against a black background which spelled out Who, the British quartet took the stage around 4 p.m. and two hours later left the throng at the sold-out show convinced they had seen one of the greatest rock 'n' roll shows ever.

The Who capped a bill presented by Electric Factory Concerts which featured three additional bands, including Philadelphia favorite, The Hooters; San Francisco's Santana, and also from Britain, The Clash.

In a way, it was the old guard versus the new: The Who, first generation British Invasion rockers, and the Clash, representing second generation or new wave which sought to displace 60s bands such as the Who and the Rolling Stones from their dominance of radio airplay and the record charts.

But it was the Who's show all the way, as several British flags waved over JFK. The group took the stage to cheers and launched into "Substitute." As soon as lead singer Roger Daltry flung his microphone around at the end of its cord, the crowd roared its approval.

The audience yelled even louder when lead guitarist Pete Townshend went through his trademark windmill guitar strums.

Townshend, wearing Docksiders, jeans and a blue T-shirt, blue headband and black jacket, also drew cheers every time he leaped in the air while playing his guitar.

The Who's lyrics dwell on brotherhood, love and understanding, rather than sex, drinking and drugs, as do those of most rock groups. Ironically, songwriter Townshend, who has forsworn use of drugs and alcohol, was entertaining thousands of teen-agers who were for the most part drunk on beer or high on marijuana.

Bassist John Entwhistle sang one song. He and drummer Kenny Jones provided solid rhythm sections. Augmenting the group's sound was Tim Drummond on keyboards.

The Who presented a polished, evenly paced show punctuated by brilliance. "Sister Disco," the fourth song into the set, was the first to spark a response from the crowd. "Behind Blue Eyes," a melodic ballad, and "Love Reign Over Me," an elegant anthem from the Who's movie "Quadrophenia," were also well received.

The biggest cheers were saved for "Teen-age Wasteland" and "Who Are You," both of which marked the 70s resurgence of the Who and their gathering of a whole new younger audience. When Townshend launched into "Pinball Wizard" and a medley from the group's rock opera "Tommy," more than 100,000 voices sang every word.

As though it were planned, the group sang "5:15," a song about a youth who is "out of my brain on the train," at 5:20 p.m.

The Who played "It's Hard," the title cut from the latest LP, and several others from their recent Warner Bros. release.

However, none of these songs measure up to the Who's material of several years ago and the audience's response was lukewarm.

The concert concluded around 6 p.m. and after a five-minute ovation, the Who came back for a two-song encore, including a Beatles-esque version of "Twist and Shout," at the end of which Townshend smashed his guitar on the stage. In all, the Who performed 22 songs.