The 2008–09 Clemson Tigers men's basketball team represented Clemson University. The head coach was Oliver Purnell. The team played its home games in Littlejohn Coliseum in Clemson, South Carolina. All games were produced and broadcast locally by the Clemson Tigers Sports Network.
Pre-season
On Tuesday, October 21, 2008, the NCAA suspended Freshman Catalin Baciu for the first five games of the season for his participation with a Romanian professional basketball team. The term of the suspension equals the number of games Baciu played as a 15-year-old for U Mobitelco Cluj, a club team that plays in Romania's top pro division, Divizia A. Although Baciu was not paid for his participation, NCAA rules prohibit student-athletes from playing on a professional team, regardless of whether they are employed. He played for a total of four minutes in his five games with U Mobitelco Cluj.
On Sunday, October 26, 2008, members of the ACC media were polled and picked Clemson to finish fifth in the conference behind North Carolina, Duke, Wake Forest and Miami respectively.
Regular season
On Sunday, November 16, 2008, The Tigers won the inaugural Charleston Classic 8-team tournament in Charleston, SC. This marks the 25th time in school history Clemson has won a regular season tournament.
On Saturday, November 22, 2008, Clemson beat Charlotte 71–70 at Halton Arena, marking the first time ever a current member of the Atlantic Coast Conference has played at Charlotte. (Miami played during there during their time as a member of the Big East).
On Wednesday, January 21, 2009, Clemson lost to North Carolina 94–70. This extended the NCAA record for the longest road losing streak against one opponent to 54 games. This also ended Clemson's streak of not losing back-to-back ACC games that dated back to the 2006–07 season.
On Sunday, January 25, 2009, with a 73–59 victory over Georgia Tech, Senior guard K. C. Rivers broke the team record for most career wins as a player with 85. The previous record of 84 was co-held Cliff Hammonds and Elden Campbell.
On Monday, February 2, 2009, EA Sports announced that Littlejohn Coliseum was one of the Top-15 toughest places to play in College Basketball. Through an online poll, Fans determined 15 finalists, whose home courts were judged to be the most difficult for opposing teams to play in. These results will form an integral part of a new game mode in the EA SPORTS NCAA Basketball videogame franchise for 2009–10.
On Wednesday, February 4, 2009, Clemson defeated No. 3 Duke in Littlejohn Coliseum by a score of 74–47. With the win, Clemson snapped a 22-game regular season losing streak to the Blue Devils dating back to January 7, 1997. The win was also Clemson's first win over a top-5 team since a victory over No. 5 Virginia in 2002.
The 27-point victory was Clemson's largest margin of victory against a top 25 team in history. The previous best was a 22-point victory margin on two occasions. Clemson defeated a fourth-ranked NC State team led by David Thompson at Clemson 92–70 on Feb 22, 1975 at Clemson, and defeated a 13th ranked Maryland team by 22 points, 93–71 on January 19, 1977, at Clemson.
The defeat was also the worst suffered by Duke since the NCAA Championship game of 1990, a 103–73 victory by UNLV on April 2, 1990. The 27-point margin was the largest for Duke in an ACC regular season game since January 18, 1984, when Wake Forest defeated Duke at Winston-Salem, 97–66.
Clemson's 10-point win over Boston College in Boston on Feb 10 was just the third ACC road win over an ACC team that finished the year with a winning record in the last 22 years. Boston College finished the ACC regular season with a 9–7 record and went to the NCAA tournament.
On Tuesday, February 17, the EA Sports Tour visited Littlejohn Coliseum as Clemson hosted Maryland. Along with judging the game day atmosphere, the tour handed out video games, T-shirts and hosted an NCAA Basketball 09 tournament leading up to the game. After their visit, Novell Thomas, the producer of the NCAA Basketball game, wrote that "Hands down, Clemson just set the bar for all hosts of the EA SPORTS Toughest Places to Play, tour." The 29-point victory was the largest margin of victory in Clemson history over Maryland, and tied for the largest margin of victory for a Clemson team against an ACC team that advanced to the NCAA Tournament. Clemson defeated Florida State in 1997–98 by 29 points.
The Tigers finished the season at 9–7, which gave them back-to-back winning seasons in the conference for the first time since the 1965–66 and 1966–67 teams did it. It is also Clemson's eleventh winning season in the conference since 1953.