10. San Antonio Spurs - Tim Duncan vs. Chauncey Billups: 31-15 record (67.4%)
The toughest opponent the Spurs ever faced in the NBA Finals was undoubtedly the Detroit Pistons in 2005. After having won a title the year before, Detroit was back on the NBA's mainstage, led by Chauncey Billups.
The team was loaded with talent, as Ben Wallace, Richard Hamilton, Rasheed Wallace, and Tayshaun Prince were also all in their primes. That series was the only time Billups would secure postseason wins over Tim Duncan, as Duncan's Spurs had swept his Timberwolves in 2001.
That sweep and the Spurs' 4-3 Finals win in 2005 gave Tim a 7-3 postseason advantage to add to his 31-15 regular-season advantage. Duncan has since said the 2005 title was his favorite of the five.
Billups retired in 2014 and has yet to make the Basketball Hall of Fame.
9. San Antonio Spurs - Tim Duncan vs. Pau Gasol: 38-17 record (69.1%)
Whether Pau was on the Memphis Grizzlies, Los Angeles Lakers, or Chicago Bulls, Tim Duncan always seemed to have Gasol's number. Many of Duncan's victories over the seven-foot Spaniard happened between 2005 and 2008 when his Spurs defeated Pau's Grizzlies 10 times in 12 games.
Still, Gasol didn't fare much better when he joined a better team in the Lakers. All in all, Duncan won 29 of 42 regular-season meetings and nine of 13 playoff games over Gasol.
Tim's squad swept Gasol's Grizzlies out of the playoffs in 2004, but the two split playoff series in 2008 and 2013 when Pau spent time in Los Angeles.
Gasol retired in 2019 after spending the tail end of his career in the Alamo City, where he averaged 10.0 points and 7.4 rebounds per game. According to Basketball-Reference's Hall of Fame probability calculator, there's a 93 percent chance he'll make the Hall based on his career numbers.