US Open: A look at 5 big upsets in the last decade

#4 2014 Semifinal: Nishikori beats Djokovic 6-4, 1-6, 7-6(4), 6-3

Nishikori takes down Djokovic to reach his first Major final

Following consecutive five-setters against Milos Raonic and Stanislas Wawrinka in each of his previous two rounds, Kei Nishikori arrived at his first Grand Slam semi-final as the overwhelming underdog against top seed Novak Djokovic.

Displaying little stage fright, the Japanese allayed any concerns of exhaustion when he took the first set for the loss of four games. Djokovic responded with greater firepower in the second to level the match at a set apiece.

In a competitive third set, Nishikori survived seven deuces to hold serve for 2-1 but failed to serve out the set at 5-3 as Djokovic broke back. To his credit though, Nishikori regained control of the match by playing a superior tie-break to take a two-sets-to-one lead.

Riding on his momentum, the Japanese broke Djokovic in the first game of the fourth set and the single break of serve would suffice as Nishikori served out the biggest win of his career to reach his maiden Grand Slam final.

In the process, Djokovic's bid to reach five consecutive US Open finals came to an end.