Japan's Nishikori, in his first tour-level event since incurring a torn tendon in his right wrist last August, swept through his first three matches dropping only one set, but found Anderson was made of sterner stuff than his previous opponents.
Anderson, using his height to great effect on serve, raced through the first set in 22 minutes but Nishikori, cheered on by an enthusiastic contingent of Japanese fans in the modest crowd, fought back in the second.
Neither player could gain an advantage in a tight third set that saw only one break point forged between them, before Anderson prevailed in the tiebreak when Nishikori netted a backhand.
It was, nevertheless, a promising week for Nishikori at the Nassau Coliseum on Long Island.
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.
He missed two consecutive grand slams -- last year's U.S. Open and last month's Australian Open -- before returning to competition in a Challenger level event on Jan. 23.
Querrey, meanwhile, was ecstatic after his first career victory over left-hander Mannarino in four meetings.
"It feels like I beat Rafa (Nadal) out there," he said.
"That (Mannarino) guy's always been so tricky. I know it's my first time beating him and it feels good. I'm so happy to get through that and be in the final."
(Reporting by Andrew Both in Adelaide, South Australia)
