Giron was not even supposed to take part in the main draw of the competition after a heartbreaking loss in the final qualifying match of the tournament.
Despite not having won an ATP title in his career, he has finished second in four singles finals and one doubles final.
Bublik has been ranked as high as world No. 34 in singles which he achieved for the first time on September 13, 2021.
The British-ace will take on his third seeded Canadian counterpart Felix Auger Aliassime in the second round of the Rotterdam Open.
They held their nerve to overcome the challenges posed by top-seeded Australians Luke Saville and John-Patrick Smith 6-7, 6-3, 10-6.