The South African will now play US Open champion Angel Cabrera, who overcame Hunter Mahan 2 and 1, despite a spirited fight back from the American, who at one point had been six holes down on the Argentinian.
Stenson and Mahan may have given way to their more experienced opponents, but there was plenty of evidence to suggest that both players are potential future winners of this title.
Visibly weary after his victory, Els described himself as really excited by the 36 hole final against Cabrera.
“It’s been a long tough week, but this is what you play for and it’s really satisfying to get there,” he said.
“I’m a little drained and I had to dig really deep to stay ahead of Henrik.”
Els, whose putting form deserted him in the morning round, rediscovered his touch on the greens in the afternoon.
“I was awful this morning on the greens but I made a change at lunch time and really tried to push through the ball. You can’t afford to be off your game here. If you are, the course will bite you.”
The suspicion that Stenson’s form, so irresistible in the opening two days of the championship, was on the wane took root in the afternoon as Els’s resilience began to make the difference.
Six hours into the match, the South African holed a five foot putt on the seventh green to go ahead for the first time.
On the ninth green, a six foot putt opened clear daylight between the pair as the six time champion, who took just 31 on the outward nine, moved to three up, with nine to play.
But Stenson lifted his game, striking back on the par three 10th by holing a 23 foot putt for a birdie.
Nervousness and fatigue from both players became increasingly evident, until Els holed a telling putt on the 15th green, leaving him three ahead with three to play. The Swede responded gamely on the 16th by attacking the flag, but was unable to hole his 14 foot putt to win the hole.
“Mentally, this game tests you so much,” Els said. “Today, with persistence, I got through it. I worked on my game all the time and that’s why I love 36 hole match play, because you have to play well all day.”