His win at this event six years ago was the biggest so far of a career that has seen him go on to taste Major Championship glory at the Masters Tournament, and the American looked every inch a Major Champion in a stunning 63 on day two at Chapultepec Golf Club.
The 29-year-old was surging through the field but had to make a smart up-and-down to save par on the 16th before a long putt on the 17th got him within one of the lead.
He had a 30 footer on the last for a share of top spot and the course record and while he could not make it, he heads into the weekend in an excellent position.
"I can't wait," he said. "Any time you come to an event like this or really any event and you get yourself into contention going into the weekend, it's always fun. It just kind of gets you going and I'll just hopefully continue the solid play and give ourselves a chance late Sunday.
"It (the 16th) was huge. I didn't really know where the course record was and honestly it wasn't really on my mind. The biggest thing was just to continue the momentum from making some quality birdies there on 15 and 14 and to just kind of continue the momentum going forward.
"I was disappointed with the way I finished yesterday with bogey on the last and so today to be able to make that putt on 16 and then to make the one on 17 just allowed me to carry the momentum going into the weekend."
Rory McIlroy enters the weekend two shots behind Reed after rescuing a 69 with three birdies in his last five holes.
The overnight leader looked all at sea as he scrambled for pars on his opening four holes and while he eventually made two bogeys, a big finish ensured the World Number One stayed right in the hunt.
"If this is the worst round out of the way, then it's not bad," he said.
"There's 36 holes left. I just stayed patient and tried to bide my time and made a couple of nice putts coming in. I guess my patience was rewarded a little bit."