Paire, competing in his first ATP Tour 500 semi-final, looked out of sorts in the opening set but found his range following a medical timeout in the second to re-tape his ankle.
The bearded 26-year-old Frenchman grew in confidence with some strong returns and big serves to secure a 1-6 6-4 6-2 win over the double defending champion, who became more tentative as the match wore on.
Paire won his first ATP Tour title on the clay at Bastad in July and will go in search of his second against French Open champion Wawrinka, who served strongly in taking out Gilles Muller of Luxembourg.
The Swiss top seed coming through 6-4 7-6(5) to reach his fourth final of the year.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
The opening set went with serve before Wawrinka broke in the seventh game and went on to close it out, dropping just four points on serve in the set.
Muller, who will break back in to the top 40 after his strong run in Japan, found a way to pressure Wawrinka in the second set by rushing the Swiss and breaking serve but failed to capitalise as he lost his own.
The set went to a tiebreak with Muller putting a backhand volley wide to hand Wawrinka the win on his first match point.
(Writing by Patrick Johnston in Singapore; editing by Amlan Chakraborty)
