While sweating profusely as the air conditioning in the AT&T Center failed to work, the future Hall of Famer recorded 21 points, 10 rebounds and three assists while shooting 9-of-10 from the field. And by doing so, he joined quite the exclusive club:
Anytime you can be paired up with Wilt Chamberlain, it's probably a good thing.
Unfortunately, Basketball-Reference.com's play finder doesn't allow us to peruse field-goal percentage records prior to the 1985-86 season, but we can at least look at the standouts who have come closest to joining the club.
Dwight Howard was on the brink of gaining entry when he dropped 21 and 14 on 5-of-6 shooting from the field back during the 2009 NBA Finals. Horace Grant (1991), Shaquille O'Neal (2004), Lamar Odom (2008) and Dale Davis (2000) are the only others on the right side of 80 percent.
Obviously, this isn't something that's easy to do.
And considering the circumstances, Duncan's performance was even more incredible.
"It was tough on both teams," San Antonio Spurs coach Gregg Popovich said to The Associated Press after the game, via NBA.com's Brian Mahoney. "They were pretty dead. We tried to get guys in and out...It was really hot out there."
Can you imagine how exhausted the 38-year-old Duncan must have been? Chamberlain was 35 years old when he accomplished the feat back in 1972, but those three years can make a big difference, especially when the air conditioning isn't working.
Now we just have to see if Duncan can match "The Stilt" throughout the rest of the Finals.
While leading his Los Angeles Lakers to the title in five games, Chamberlain averaged 19.4 points, 23.2 rebounds and 2.6 assists per game while shooting 60 percent from the field, per Basketball-Reference.com.
It looks as though Duncan has his work cut out for him.