It's been fitting for Tim Duncan to be reaching milestones at the end of his career. He's become the San Antonio Spurs all time points leader and broke the NBA's record for all time playoff blocks. So it was fitting for Duncan to reach another milestone: 2,500 career blocks.
This block wasn't just an ordinary block though. It was more of a “I hope no one has a recording of it” type of block. Raptors' Andrew Bargani didn't expect it. He tried to go carelessly to the basket, maybe hoping Duncan was too old to catch up to him. Either way, Duncan blocked him and Bargani didn't look too flattering in the process.
This is a huge accomplishment for Duncan as he's the ninth player all time to achieve it. Even if it's a big deal, Duncan goes along with it the usual Spurs “quiet yet dominating” sort of way.