Djokovic edged out Wawrinka 2-6, 7-6(7-4), 3-6, 6-3, 6-4 in four hours and eight minutes at the Arthur Ashe Stadium here.
Wawrinka hit the ground running, dismantling the top seed in a easy first set win. The Swiss had clearly learned a thing or two from his former Davis Cup doubles partner Roger Federer on how to time those single-handed backhands as he hit 10 winners to the Serb's six.
Djokovic had the Swiss to thank for handing him the second set. Wawrinka smacked a whopping 21 winners to Djokovic's 12 but 19 unforced errors cost him the set and probably the match.
Djokovic edged out Wawrinka 2-6, 7-6(7-4), 3-6, 6-3, 6-4
However, to his credit, the first-time major semi-finalist recovered to win the third set in just 34 minutes.
Djokovic who had only lost one set in his five previous matches - to No. 21 seed Mikhail Youzhny in the quarter-finals took a 4-1 lead in the fourth. Things only got better for the World No.1 as the Swiss took an off-court three-minute time-out after which the Serb easily closed out the set.
With the match going into the fifth set hot conditions endurance came into play. Wawrinka's injury also started to show but that didn't seem to deter him.
In a physically draining third game, which lasted 21 minutes and 12 deuce points, Wawrinka saved five break points before holding serve.
Djokovic hit back almost instantly levelling the set 2-2. Wawrinka finally began show signs of weakness as tiredness creeped in. The Serb finally gained control of the match and held his service game to book a final showdown between the winner of the match between Rafael Nadal and Richard Gasquet later in the day.