Woods improved to 40-2 on the PGA Tour when he had the outright lead going into the final round, the last two wins with McDowell at his side. Woods last won while ahead at Bay Hill a year ago.
"The way Tiger was playing, I was always in chase mode," McDowell said. "He was always going to be a tough guy to catch. Fair play to him. He played fantastic golf the last couple of days."
Woods finished minus 19 at 269 and earned $1.5 million in winning this World Golf Championship for the seventh time.
McIlroy's week ended on a happy note.
Not only did he finish the tournament, he might have turned the corner with a bogey-free 65. McIlroy opened with a 7-iron into 18 feet for eagle, which he called one of the best shots he hit. He shot a 32 on the back nine for a round that surprised him considering how far away he felt when he arrived at Doral.
"Just goes to show, it's not as far away as you think," McIlroy said. "That's been one of my problems. I always think when I'm playing bad that it's further away than it is. That's just where I have to stay patient ... and know that if I put in the hard work, that the results will bear fruit. Whether that's sooner or later, it doesn't really matter."
McIlroy said he won't add a tournament the next two weeks, returning at the Houston Open before going to the Masters. He is signed up for the member-guest a week from Monday at The Medalist Club, presumably as the guest of former NBA great Michael Jordan.
"He's asked me, so depending on what my schedule is and where I have to be ... we'll see," he said.
Scott had the low round of the tournament with eight birdies in his round of 64.
That's what McDowell, Mickelson and Stricker would have needed to have any chance of catching Woods. As he did early in third round, McDowell gave it his best shot, only to have Woods answer on every occasion.
McDowell two-putted for birdie on the par-5 opening hole as Woods blasted a shot from a buried lie at the back of the green well past the pin and off the green. He had to chip close just to save par. McDowell hit his approach on the second hole to 7 feet and looked as if he might pick up another shot.
In what might have been the most significant putt Woods made, he buried an 18-footer for birdie.
That's how it went all weekend. Woods never gave anyone a chance, and he didn't give anyone much hope. His lead was back to four shots, he hit an 8-iron to 4 feet on the par-3 fourth hole, and no one seriously challenged him the rest of the way.
Mickelson hit a 200-yard shot into the breeze and over the water to a foot for a tap-in birdie on the par-5 eighth to get within four shots with 10 holes to play. He missed far too many short putts, however, making bogey on the ninth and 11th holes to fall too far back to matter.
That allowed another easy walk up the 18th hole for Woods to collect another WGC title, another seven-figure check, and offer another reminder that he is closer than ever to getting back to the top of golf.
Woods now has won over $24 million in the WGCs alone since the series began in 1999, winning 43 percent of the tournaments. This was his 76th career win on tour, leaving him six short of the record 82 wins by Sam Snead.