When Memphis was beaten by Tennessee, 66-62, last Feb. 23, there was no longer any chance that an undefeated team would reach the NCAA men's basketball tournament this year.

So for another year, the 1991 University of Nevada, Las Vegas Runnin' Rebels remain the last undefeated team to reach the NCAA tournament and also the last unbeaten team to make it to the Final Four.

The 1976 Indiana team, under coach Bobby Knight, still stands as the last unbeaten team to make it all the way to the national championship with a perfect record.

Only 17 unbeaten teams have reached the NCAA men's basketball tournament in the 70 years of the event, while a mere seven of them made it all the way through the tournament to win the championship with an unblemished record. Four of those unbeaten champions were UCLA teams under coach John Wooden in 1964, 1967, 1972 and 1973.

The other two unbeaten champions were San Francisco with Bill Russell in 1956 and the 1957 North Carolina Tar Heels, who beat Wilt Chamberlain's Kansas in triple overtime.

Another unbeaten team from the Hoosier state lost its last game of the season when Magic Johnson and Michigan State beat Larry Byrd's Indiana State in the 1979 NCAA championship game at the University of Utah.

Although coach John Calipari's Memphis team suffered one loss in the recent regular season, and although it was often disparaged as a member of the lightly regarded Conference USA, the Tigers proved their No. 1 seed was deserved when they reached the Final Four this weekend. Memphis is only the 55th team in NCAA history to enter the tournament with one loss, and only the 23rd team with one defeat to make it to the Final Four. Six of these one-defeat teams, including three more John Wooden UCLA teams, won the NCAA crown.

No team with but one loss has taken the NCAA Basketball Championship since coach Norm Sloan's 1974 N.C. State Wolfpack (26-1) beat John Wooden's UCLA in overtime in the semifinals and then beat coach Al McGuire's Marquette in the title game.

It was not until the 13th NCAA basketball tournament in 1951 that an undefeated team entered the field that was expanded that year from the original eight teams to 16. That unbeaten team was my alma mater, Columbia, which was 21-0 under coach Lou Rossini during the regular season and riding a two-season 31-game winning streak.

However, Columbia did not go very far as the Lions lost in the first round to Illinois, 79-71, at Madison Square Garden.

Years later, looking back on that game in which Jack Molinas, Columbia's All-American player, scored 20 points, one suspected strongly that Molinas might have done much better that night in the Garden. We questioned his motives after he was exposed as a heavy gambler and was banned from the NBA, sent to prison as a basketball game fixer and eventually assassinated in 1975 in what was apparently a mob hit.

The late Jack Rohan, a close friend of mine and a member of that 1951 Columbia team who later became the most successful Columbia basketball coach to date, told me years ago that he never knew which Molinas was going to show up to play any given night -- the gambling point shaver or the superb athlete who wanted to win.

Columbia, which led by eight points at the half, suffered in the last 20 minutes when Molinas missed shot after shot and committed a few turnovers.

Unfortunately for the Lions, Molinas was so good yet so bad.

Three times in NCAA history a pair of undefeated teams was in the tournament field although only one of those six teams, Indiana in 1976, managed to win the title. The first set of unbeaten twins came in 1968 when Houston and St. Bonaventure had 28-0 and 22-0 records, respectively, as the tournament began. But UCLA, which suffered only one loss, won that championship in Lew Alcindor's junior season.

I had the pleasure of covering all of the Final Fours I am writing about here, including all 10 of John Wooden's UCLA title years. That 1968 Final Four stands out because of the absolute power of UCLA in what was pure revenge against Houston.

The Bruins' only loss that season was a 71-69 defeat to coach Guy Lewis' Cougars at the Houston Astrodome, Jan. 20, 1968. This upset that ended UCLA's 47-game winning streak was billed as the "game of the century." It was the first regular-season college basketball game to be nationally televised, which was a big deal 40 years ago. More than 52,000 spectators filled the Astrodome, setting a college basketball record.

It was the battle of the unbeatens and the big men -- Alcindor against Houston's Elvin Hayes. And there were some excellent members in each supporting cast -- UCLA's Lucius Allen, Mike Warren and Lynn Shackelford plus Houston's Don Chaney and Theodis Lee.

Alcindor suffered a severe scratch to his right eye early in the game. That is one reason Alcindor, who changed his name to Kareem Abdul Jabbar, wore goggle-style glasses during games for the remainder of his college and professional careers.

When these teams met in the semifinal round of the NCAA tournament or the opening round of the Final Four in the Los Angeles Memorial Sports Arena the next month, a healthy Alcindor and UCLA poured it on for a 101-68 triumph. In fact, the Bruins opened the game by letting everyone know they were out for serious retribution as they raced to a huge lead so quickly that Guy Lewis didn't think to call time until the score was 18-2. It was all over by then and everyone in the Los Angeles Arena knew it.

Two days later, UCLA easily beat coach Dean Smith's North Carolina, 78-55, for the 1968 title.

Coincidentally, when UCLA and Houston met at the Astrodome, the game promoters had to get a basketball court floor from somewhere since the Astrodome was built for football and baseball. They were able to rent the floor from the Los Angeles Memorial Sports Arena for that "game of the century." Thus the two teams met twice that year on the same basketball court with each team winning once, although UCLA won the game that really counted.

When Indiana reached the Final Four of 1976 without a loss, the Hoosiers were not alone in their perfection to that point. Rutgers was also unbeaten as it joined Indiana, Michigan and UCLA in the Final Four.

However, the Scarlet Knights, in their first such lofty basketball success, were beaten by Michigan in the initial semifinal game, 86-70. Two days later, Rutgers, whose All-American star, Phil Sellers, tried his best, lost to UCLA in the consolation game for third place, 106-92.

When UNLV made it to the Final Four in 1991 with a perfect record, there was another game of revenge that cost the Runnin' Rebels dearly.

They trounced coach Mike Krzyzewski's Duke Blue Devils, 103-73, in the previous year's NCAA championship game. It was payback time for Duke in 1991, however, as the Blue Devils, not quite able to win by 30 points, settled for the narrow 79-77 victory over coach Jerry Tarkanian's UNLV in the national semifinals.

UNLV is the only unbeaten team in the tourney since the field was enlarged to 64 teams in 1985 and then 65 in 2001. Since 1985 the champion had to win six games in the tournament. Prior to that, all championship teams won five or less games in the tournament. Each of Wooden's four unbeaten UCLA championship teams had a 4-0 tournament record.

Yet UNLV may proudly think of itself as the most recent member of a very elite club. There have been 2,619 teams in the NCAA Men's Basketball Championship Tournament since its inception in 1939 when eight teams were entered and the University of Oregon won the first title. If only 17 of these teams were undefeated going into an NCAA tournament, that means the Runnin' Rebels, my own Columbia, all those UCLA perfect teams and the other unbeatens make up a minuscule 0.65 per cent of the entries. That is truly elite.

Gordon White served 43 years as a sports reporter for The New York Times. His e-mail is sports@thepilot.com.