The meeting lasted 1 hour 42 minutes and ended with a score of 4:6, 6:0, 6:3 in favor of the seventh racket of the world.
The 24-year-old Russian athlete significantly surpassed his opponent in points won on the first serve (93% vs. 62%), which was a key indicator.
Andrey also filed 15 times right through, while the Korean made seven aces.
In the quarterfinals, Rublev will play with the American Mackenzie McDonald, who defeated the Serb Filip Krajinovic.
Earlier it was reported that Alexander Zverev was disqualified for unsportsmanlike behavior at the ATP tournament in Acapulco.