Duncan's career is pretty much an unending stream of classic performances. He averaged 24-17-5-1-5 in that 2003 Finals.
We're talking about a guy who averaged 20-10-3-1-4 in his very first playoff series in 1998...being the same guy who just averaged 18-11-3-1-2 in his most recent playoff series in 2015.
32, 10, and 2 in his very first playoff game...27, 11, and 2 in his most recent playoff game.
Closed out the 1999 Finals in 5 games for his 1st championship...closed out the 2014 Finals in 5 games for his 5th championship.
Think about it this way...when Duncan was averaging 21 and 9 (with dominant defense) in the 1998 playoffs, Kobe was still coming off the bench behind Eddie Jones and averaging 8.6/1.8/1.5 in the playoffs. When Duncan was averaging 18 and 11 (and still killing it on D) in the 2015 playoffs...Kobe hadn't finished a season in three years.