LEXINGTON, Ky. (AP) Lou Tsioropoulos, a member of Kentucky's 1951 NCAA national championship team and the unbeaten `53-54 squad who went on to win two NBA titles with the Boston Celtics, has died. He was 84.

Tsioropoulos' nephew, Michael Johnson, said Wednesday night that his uncle died Saturday in Louisville of natural causes. A memorial service was held there Wednesday. He would have turned 85 on Monday.

The 6-foot-5, 190-pound Tsioropoulos teamed with Naismith Memorial Hall of Famers Frank Ramsey and Cliff Hagan to beat Kansas State 68-58 in 1951 to win the third of Kentucky's four NCAA titles under coach Adolph Rupp. Three years later Tsioropoulos helped Kentucky finish 25-0 and complete the school's only undefeated season.

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Tsioropoulos averaged 14.5 points and 9.6 rebounds for that Wildcats team, which declined an NCAA Tournament berth. He finished with career averages of 8.4 points and 8.3 rebounds and the school retired his No. 16 jersey.

''We are terribly saddened to hear Lou Tsioropoulos passed away over the weekend,'' Kentucky athletic director Mitch Barnhart said in a statement. ''Lou was and always will be a Wildcat legend. His accomplishments speak for themselves: the national championship season in 1951, an undefeated season in 1953-54 and a two-time NBA champion.

''We are grateful we can forever honor his contributions to the university with the retirement of his jersey in the Rupp Arena rafters. Our prayers and thoughts go out to the Tsioropoulos family.''

A seventh-round draft choice of the Celtics in 1953, he spent time in the U.S. Air Force before joining the team in 1956. He won a title that season and in `58-'59 as a backup for Naismith Memorial Hall of Famer Tommy Heinsohn.

Tsioropoulos averaged 5.8 points and 4.8 rebounds during a three-year pro career.

''He was a prototype for the sixth man that was developed over the years,'' Heinsohn said in a statement from the Celtics. ''He was a fun guy and probably would have had a longer career as a Celtic if it wasn't for injuries. My heart goes out to Lou's family and he will be missed.''

The Celtics' statement added that Tsioropoulos ''had a special connection to the Celtics family both as a hometown hero as well as being part of the organization's first two championships.''

Tsioropoulos later coached basketball at Louisville's duPont Manual High School from 1963-69.

Born in Lynn, Massachusetts, Louis Charles Tsioropoulos excelled in football and basketball in high school before playing the latter at Kentucky under Rupp. Former Wildcats manager Humzey Yessin recalled Tsioropoulos on Wednesday as ''one of the best rebounders we ever had.''

Tsioropoulos' size and dual talent drew the attention of then-Kentucky football coach Paul ''Bear'' Bryant, who went on to become a legend coaching at Alabama. Yessin added that Bryant would ''ask Rupp to let him have Tsioropoulos because he knew he had played football.''

Tsioropoulos is survived by wife Jan, daughter Tara, a niece and several nephews.