Novak Djokovic defeated Nikolay Davydenko in the final, 6–1, 7–5 to win the singles tennis title at the 2008 Tennis Masters Cup. It was his first Tour Finals title, and the first of an eventual record seven such titles. Roger Federer was the two-time defending champion, but was eliminated in the round-robin stage. This marked the only time in his career that he was eliminated before the semifinals. Future champion Andy Murray made his tournament debut; he was defeated by Davydenko in the semifinals. Jo-Wilfried Tsonga, Juan Martín del Potro, Gilles Simon, and Radek Štěpánek (as an alternate who replaced Andy Roddick) also made their tournament debuts. Štěpánek, playing as the world No. 27, was the lowest-ranked player ever to compete in the Tour Finals. Rafael Nadal qualified as the world No. 1, but withdrew before the tournament with a knee injury, where he was replaced by Simon.

Seeds

• # Roger Federer (round robin) • # 🇷🇸 Novak Djokovic (champion) • # 🇬🇧 Andy Murray (semifinals) • # 🇷🇺 Nikolay Davydenko (final) • # 🇺🇸 Andy Roddick (round robin, withdrew due to a right ankle injury) • # 🇫🇷 Jo-Wilfried Tsonga (round robin) • # 🇦🇷 Juan Martín del Potro (round robin) • # 🇫🇷 Gilles Simon (semifinals)

Alternates

• # 🇨🇿 Radek Štěpánek (replaced Roddick, round robin) • # 🇩🇪 Nicolas Kiefer (Did not play)

Draw

Finals

Red group

''Standings are determined by: 1. number of wins; 2. number of matches; 3. in two-players-ties, head-to-head records; 4. in three-players-ties, percentage of sets won, or of games won; 5. steering-committee decision.''

Gold group

''Standings are determined by: 1. number of wins; 2. number of matches; 3. in two-players-ties, head-to-head records; 4. in three-players-ties, percentage of sets won, or of games won; 5. steering-committee decision.''