Antonsen, who won the tournament in Kuala Lumpur in 2024, struggled to settle into his normal stylish stride at the beginning of the match and was behind 4-7 before he got going.
Winning five successive points, Antonsen turned 9-10 into 14-10 and claimed the set comfortably.
The Dane was also a slow starter in the second set. He was behind 3-7 before he made it 10-9. Antonsen then again made a decisive move by winning five successive points to turn 12-12 into 17-12.
After a long duel, he took advantage of his first match point.
In the women's singles tournament Mia Blichfeldt was clearly hampered by an injury when she lost in the second round to Ratchanok Intanon from Thailand.
The Dane, who is ranked 20th in the world, gave it a shot against the world's nr. 7, but lost clearly in two sets 8-21, 7-21.
Line Kjaersfeldt is still to play a match in the tournament after the Chinese world number five, Han Yue, withdrew.
This means Kjaersfeldt is ready for the quarterfinals, where her opponent will be the South Korean world nr. seven, An Se Young.