Manley, who is 174th in the European Tours Order of Merit, birdied his last two holes at the Oceanico Victoria Golf Course.
Im very delighted, the Welshman said. I hit lots of fairways and made a few birdies. The greens were a bit bumpy and it was not the best of draws but for some reason the putts just went in.
Hopefully, I can keep it going. I could use the money.
Jyoti Randhawa was tied for second with Alvaro Quiros and Mark Foster, all one stroke behind Manley. Seven players were another stroke back, including Martin Erlandsson, Andrew McLardy, Soren Kjeldsen and Graeme McDowell.
Foster had seven birdies in his round'including three on the first six holes. His only bogey came on the seventh hole. Quiros, who finished fourth at last weeks Madrid Masters, also had seven birdies and a bogey.
Robert Karlsson (69), aiming to extend his lead at the top of the European Order of Merit, holed a 40-foot putt on his second hole but was inconsistent. The 39-year-old Swede, who has won his past two European tour events, had seven birdies and four bogeys.
Lee Westwood (72) still has a chance to overtake Karlsson in the money list, despite not winning a tournament this year. Like Karlsson, he birdied two of his first three holes before fading'finding water with his second shot at the 17th for a double-bogey.