The defending champion at Augusta outdueled Scott Verplank yesterday to win the Houston Open in Humble, Texas, by three shots, his first victory since earning his third green jacket last April.

The win moved Mickelson’s world ranking to No. 3, while Tiger Woods dropped to No. 7. It’s the first time Mickelson has been ahead of Woods in the ranking since the week before Woods won the 1997 Masters for his first major championship.

“It feels really good for me to have played well and gained some momentum heading into next week,’’ Mickelson said. “I needed to have a week where I kind of put it together.’’

Mickelson shot a 7-under-par 65, the lowest closing score by a winner this year, to finish at 20 under.

He was 16 under over his final 36 holes, after tying the course record with a 63 Saturday, his lowest round in two years. He won for the fifth straight time when he’s shot 64 or better in at least one of the rounds.

“I’ve been saying all year, ‘I’m playing well, but I’m not getting the scores out of it, and I’m just kind of having a lapse of focus,’ ’’ he said. “It was a great week in that regard.’’

Tour rookie and second-round leader Chris Kirk (67) tied Verplank (68) at 17 under.

Mickelson is hoping he can repeat some history at Augusta this week. The 39-time tour winner is the last player to win the week prior to a Masters victory, capturing the BellSouth Classic in 2006 before earning his second green jacket. The Houston Open became the run-up event to Augusta in 2007.

While many top players, including Woods and world No. 1 Martin Kaymer sat out this week, Mickelson saw no disadvantage in coming here and trying to win. Anthony Kim won last year and finished third at the Masters.

“I think it’s nothing but a plus to be able to gain some momentum,’’ Mickelson said, “especially given that I haven’t had the results and the scores that I wanted earlier in the year.’’

Verplank, meanwhile, needed a victory just to get to Augusta. The 46-year-old would’ve become the fifth-oldest champion on tour in the last five years.

LPGA — At Rancho Mirage, Calif., Stacy Lewis held off defending champion Yani Tseng to win the Kraft Nabisco Championship by three strokes, earning her first tour title in the year’s first major.

Lewis shot a 3-under 69 to finish at 13-under 275, rallying from an early two-stroke deficit while going head to head with the world’s top-ranked player.

She punctuated a tenacious back nine in gusty wind at Mission Hills with an improbable 20-foot par putt from the fringe on the 17th hole, prompting a celebration in the raucous gallery.

Tseng shot a 74 with four bogeys, losing focus in her quest for her fifth worldwide title this year. Lewis bogeyed the 15th hole to allow Tseng to pull within one stroke, but Tseng bogeyed the next two holes.

“I can’t even believe it,’’ said Lewis, who overcame scoliosis to become an elite golfer. “I’ve felt like I’m going to throw up all day. It’s awesome . . . I just couldn’t believe I made it [on the 17th hole]. I thought I had a good shot from there, but I just tried to stay calm.’’

After sinking her final 3-foot putt on the 18th, Lewis raised her arms in disbelief before hugging Tseng and her caddie, and several players quickly doused her with beer in the LPGA tradition for a first-time winner.

Lewis and her family then took the Kraft Nabisco’s traditional winner’s leap into Poppie’s Pond, holding hands while running to the water, with Lewis and her caddie doing modified cannonballs. However, Lewis’s mother, Carol, got her foot stuck in the rough and badly injured her left leg on the leap, going to a local hospital.

Morgan Pressel, Katie Futcher, and Angela Stanford finished nine strokes behind Lewis in a third-place tie. Michelle Wie (75) and Pressel (76) both faltered badly in their final rounds after starting the day within striking distance of Tseng and Lewis, with Wie falling into sixth place — still her best finish in a major since 2006.

Champions — Tom Lehman, who began the day with a one-shot lead over Jeff Sluman, pulled away for his second victory of the season with a 69 at the Mississippi Gulf Resort Classic in Saucier, Miss.

Sluman, Nick Price, and David Frost tied for second, four shots back. Hale Irwin finished tied for seventh, earning his 200th top-10 finish on the Champions Tour.

European — David Horsey of England had a birdie on the second extra hole of a three-way playoff to earn his second tour title, taking the Trophee Hassan II in Agadir, Morocco, after a round of 67 that included a hole-in-one.