Ranked third in the world, Els posted a 3 and 2 victory over Singh in a rematch of the 1997 final. The win gives the South African a chance at his fourth title in this event.
Els will have to get through Garcia, the fifth-ranked player in the world from Spain who is buying his house in Orlando, Fla.
"No, the price won't change if he beats me," said Els, who won this event from 1994-96. "That deal's already done."
"I am going to try as hard as I can, and so is he," added Garcia, who dumped Michael Campbell of New Zealand, 2 and 1. "It's always nice to play against a close friend."
Els didn't play as well as he did Friday, when he had the equivalent of a 12-under-par 60 over the first 18 holes against Colin Montgomerie. But he didn't need to be as good Saturday, with Singh stumbling out of the blocks.
Singh bogeyed the first three holes to give Els a 3-up lead. The Fiji native trimmed the deficit to a hole through 15, but Els built a 5-up lead through 23 holes and held off a late run by Singh.
Els is closing in on his 11th career European Tour title and third of the season. He began the week second to fellow South African Retief Goosen in the Order of Merit.
Garcia put together one of his typical rallies, having erased a four-hole deficit in the second round. The Spaniard led for the first time when he birdied the 30th hole - the par-5 12th - and went 2-up when Campbell followed with a bogey.