Nishikori reached the fourth round at the US Open in 2008 and at Wimbledon this year in his best prior grand slam results.
Since January, Nishikori has been coached by the former world number two Michael Chang of the USA, who won the French Open in 1989 at the age 17.
In February, Nishikori took a singles title on an indoor hard court at Memphis before winning again in April at Barcelona on clay.
Nishikori today also becomes the first Asian male to make a grand slam final.
Prior to todayís meeting Nishikori was tied head to head 1-1 with Djokovic losing in the duoís last meeting 2-6, 7-6(7-4), 6-0 in Basel in 2011.
In semifinal number two, the 25 year old Marin Cilic used an overpowering serve to top the five time US Open champion Federer 6-3, 6-4, 6-4 to reach his first grand slam final.
Prior to today, the Croatian had been 0-5 head to head versus Federer. In his previous best grand slam result, Cilic reached the semifinals at the Australian Open in 2010.
And in yet another nod to the current trend of throw back grand slam champion coaches, Cilic has been coached recently by the 2001 Wimbledon champion Goran Ivanisevic also of Croatia.
Mondayís US Open final will be the first menís grand slam final since the 2005 Australian Open final that did not feature either Djokovic, Federer or Rafael Nadal of Spain.
Head to head, Nishikori leads Cilic 5-2 with Nishikori winning the pairís last meeting in the quarterfinals at Barcelona 6-1, 6-3.