The 32-year-old defending champion from China came alive in the deciding game to beat Lee Zii Jia 8-21, 21-19, 21-5 in a 70-minute men's singles last 16 match at the Musashino Forest Sports Plaza on Thursday.
In the quarter-finals, Chen Long will take on second seed Chou Tien-chen of Taiwan on Saturday.
Chen Long started off slow while Zii Jia, who hurt his wrist in the early stage of the game, got off to an aggressive start to take the opener.
Not affected by the opening game setback, the highly experienced Chen Long picked up pace and kept his cool to take the second game.
Malaysians were hoping for Zii Jia to rise to the occasion in his first Olympics but instead, it was Chen Long who took a commanding lead to head all the way for a win. It was a sweet revenge for the lanky player who had lost to Zii Jia in the quarter-finals of the All-England, 15 months ago.
Five years ago, Chen Long also crushed our hopes when he defeated Lee Chong Wei in the final at the Rio Olympics.