Woods never trailed, winning the opening hole when Toms three-putted from about 45 feet, missing the second from seven feet.
Toms had to hole an eight-foot par putt on the next, and he fell two holes behind on the par-5 third hole when Woods pitched to six feet and made birdie.
It was the first time all week that Toms was more than one hole down.
He got it back to one with a 12-foot birdie, but another three-putt bogey on No. 5 put him in a tough spot -- waiting for Woods to make a mistake.
Woods wasn't as crisp as he had been the first five rounds, but he applied enormous pressure off the tee on a sunny, calm morning at La Costa.
He didn't miss a fairway until the par-5 11th, and even then managed to halve the hole with a wedge into six feet for birdie.
Toms won only two holes -- his birdie on No. 4, and a bogey by Woods on the ninth. Woods has made only two bogeys in 95 holes this week, both times by three-putting at No. 9.
Woods was 2 up at the turn, then won the 10th with a par when Toms hit into the rough and had to chip out. Woods won the 14th when Toms hit his approach over the green, into the thick collar of a bunker. He chipped through the green and missed his putt.
Woods is in the final for the second time in four years. He and Darren Clarke were tied after 18 holes in the 2000 Accenture Match Play Championship, and Clarke went on to win, 4 and 3.
A victory by Woods would give him a career sweep of the four World Golf Championship events, which started in 1999.