Garcia did not drop a shot as he tamed the windy conditions in a round of 65 to move to 12 under par on the Houston Golf Club course in suburban Humble.
The 34-year-old broke through on the PGA Tour by capturing the first of eight titles at the 2001 Colonial Championship in Fort Worth and then three years later succeeding at the Byron Nelson Classic in Irving.
Garcia capped his round by sandwiching a fourth-hole eagle either side of two birdies, and then also birdied three holes in succession from the 12th.
"I was thinking I would be able to shoot three, four-under," he said. "So to be able to shoot seven under in those conditions was really, really nice."
However, Garcia continues to tread water in a pool of players still carrying the tag 'One of the best golfers never to win a major.' He has not looked like making the breakthrough since losing the 2008 PGA Championship to Ireland's Padraig Harrington, but in this form he does now look a genuine threat to become the third Spanish-born champion at Augusta National.
He said: "It's difficult to say how good my golf is compared to the past, but I would say it's the best it's been since 2008 PGA. I felt really, really good there at Oakland Hills and I was close to winning."
The 25-times winner also is back in a good place in his off-course life thanks to German-born girlfriend, Katharina Boehm, who caddied for Garcia when he ended a year-long drought in capturing last December's Thailand Championship in Bangkok.
He added: "There is no doubt I am in a comfortable place. Everybody knows pretty much what has gone on in my life, and it's never fun to go through some of those emotions. But you get to learn from those downs and to really enjoy the highs. So I am definitely happier outside the golf course, which makes me happy on the golf course."
Double major winning Rory McIlroy said his game is around 85% heading to the Masters, despite shooting a 71 to move to three under par. Lee Westwood is assured of making the Houston Open cut in signing for a 72 to fall back to level par, but fellow Ryder Cup star Nicolas Colsaerts kissed goodbye to his hopes of heading to Augusta after withdrawing following his first-round 76.