The Serb, attempting to become the first player since Steffi Graf in 1988 to win the "Golden Slam" (all four majors and the Olympic gold medal in the same season) hit 23 winners and wasn't broken in the 72-minute match.
Top seed makes light work of Bolivian in Tokyo opener
Djokovic had Dellien under immediate pressure to begin the match. After a swift hold, he took the Bolivian to deuce in his first service game and held three break points in the fourth game before Dellien held on to make the score 2-2.
From that point on, the heavy gold medal favorite won five straight games, breaking after Dellien sliced into the net after a Djokovic backhand landed just inside the line and powering a forehand winner on set point to claim the first set and the opening game of the second.
The world number 139 stayed in touch for a couple of more games before Djokovic broke things open, setting up triple break point a backhand winner down the line and converting on his first opportunity after Dellien missed long with a forehand with to take a 3-1 advantage.
The Serb cruised through his final two service games without dropping a point and finished the match with a break on his second opportunity of the game, looking every bit the player that has dominated men's tennis in 2021.