Djokovic, the event's third seed, held a 6-0, 1-0 advantage over Radek Stepanek when the Czech was unable to continue because of heat exhaustion.

Wawrinka was leading sixth-seeded Andy Roddick 3-0 before the American succumbed to a back ailment. Roddick pulled up awkwardly after Wawrinka hit a forehand winner in the third game and requested a trainer on the changeover.

In a brief return to the court, Roddick double-faulted and then quit the match.

The 22-year-old Wawrinka, from Switzerland, is the first unseeded player to advance to the ATP Masters Series final since Spain's Felix Mantilla beat Roger Federer in this tournament's 2003 final.

Wawrinka knocked off the top-seeded and world No. 1 Federer in the quarterfinals Friday.

Sunday's Djokovic-Wawrinka winner will earn $558,000.