It was still early in the match, but Tom Jennings was 140 balls ahead as Larry Lisciotti stared at the table. Fourteen balls sat in a tight cluster that was shaped roughly like the continent of Africa. Inside the pack, at about where Angola would be, the 4 ball was pinned against the 11. Played correctly, the 4 would drop straight into the corner pocket. Lisciotti's problem was that to hit the 4 ball he first would have to bank the cue ball off the side rail at the precise angle. It would be a risky shot, made riskier because Lisciotti was tense. So far, little had gone right in his match with Jennings.

Lisciotti cleared his throat. "Why not?" he muttered. Hunched over the table, a medallion dangling from his neck, he aimed, drew back his cue stick and drilled the cue ball toward the rail.

The action was taking place on the second night of the $10,000 Challenge of the Champions, which a fortnight ago brought the two reigning U.S. straight-pool champions together for the first time. The two U.S. champions? Indeed. Jennings won the 1976 U.S. Open, an annual tournament sponsored by the Billiard Congress of America, but his victory was tarnished. Before the Open, the BCA had announced it was cutting its prize money from $50,000 to $25,000. In protest, a group of 32 players, including most of the best shooters, had quit the BCA, formed the Professional Pool Players Association and held a championship at Asbury Park, N.J. Lisciotti won that one, clinching his victory by winning two consecutive games from Steve Mizerak, who until then had been regarded as the prince of pool.

The game that Lisciotti and Jennings played was 1,000-point catch-up, 200 points a block. Simply put, play on the first night would end when the leading scorer had sunk 200 balls. The second night, play would end when the leader had 400, and so on for five nights. In each block, the leader could advance by only 200 points, but the trailer could take the lead by making up his deficit and then sinking 200 balls before his opponent did. This format clearly favored a streak player—one specializing in long runs—over a consistent shooter, and it was designed to prevent a runaway. That way the bettors would stay interested.

And there were plenty of them packed into the back room at Hopkins Billiards in Green Brook, N.J., where about 250 spectators a night sat in a little gallery or lounged atop the half a dozen other pool tables stored there. Those who had come to bet were getting some added entertainment, because Lisciotti vs. Jennings was not merely a match of national-championship pretenders. It was also a struggle between two different visions of what pool should be—the hustlers' game and the clean, well-lit game the BCA would like pool to become.

Jennings, the BCA's man, exudes suburbia. He is 26, single, and lives with his folks and three younger siblings in a colonial house in Edison, N.J. He teaches calculus at nearby Middlesex County College and is working toward a Ph.D. in math from Rutgers. He is bright, thoughtful, articulate and reserved.

In 1966, when Jennings first set foot in a poolroom, he was accompanied by his father, an accountant at J. C. Penney, who shoots skillfully enough to sink an entire rack if all goes well. Two years later, the 17-year-old Jennings was rattling off 100-ball runs, accepting challenges—non-betting only—from the top neighborhood players and, in poolroom parlance, beating them like drums. "I have the capacity to run many balls," he says, "250, 275, 300. Not many players run them like that. At least not consistently." As a preparation for the '76 Open, Jennings invented a game for himself. For six weeks he practiced every night, the sessions ending whenever he made 100 balls in a row. Not once did he have to stay longer than an hour and a half.

A 100-ball run is nowhere near Willie Mosconi's BCA record of 526—an accomplishment so astounding that few players today believe that he did it. Only once in the history of the BCA Open has a player run 150 straight, and that was a dozen years ago.

Among the pros, Jennings is viewed as a conservative shotmaker and cautious tactician, although he does not seem so because he has a very long bridge and a freewheeling stroke. He uses a 64-inch cue stick, the longest made and the most difficult to control. Experts also contend that Jennings lacks the seasoning—the nerve-dulling kind that comes only from gambling—to be a champion of the first rank. When the cash goes down, they say, practice runs, no matter how long, are as useless as buggy whips. Jennings disagrees. "Pool is a form of expression," he says. "I'm content to practice and develop my skills."

Well, maybe not perfectly content. After winning the Open, Jennings set out to market his title. He designed a trick shot he hoped Alka-Seltzer would use in a TV commercial. He places two tablets near two glasses of water on the head rail and then drills a cue ball into the cushion. Plop-plop, fizz-fizz—the tablets jump off the rail and land in the glasses. Jennings also mailed a packet of ideas to Cleveland sports impresario Mark McCormack, visited New York City publicist Joey Goldstein and phoned Michael Trope, the Los Angeles-based football players' agent. All that materialized from these efforts was an endorsement for calfskin gloves that began, " Tom Jennings' hands are worth millions." For payment, the million-dollar hands got $500.