Sathiyan, the lone Indian in the main draw, had to play out of his skin to down Freitas 4-3 and enter the Round of 16 in this elite Platinum tournament late on Thursday night.
Ranked No. 35 currently, the Indian lost the first game 4-11 but fought back in his usual aggressive way, winning the next games 11-9, 11-9.
But the Portuguese was not ready to give up, clawing his way back into the contest by clinching the next two games 11-8, 11-6.
A valiant Sathiyan managed to level the match 3-3, battling to a 11-9 victory. With everything to play for in the decider, he showed great temperament to race to a 11-7 win for a sensational victory.
He next plays China's World No. 2 Xu Xin for a place in the quarter-finals.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)