The 28-year-old from Aberdeen began the Andalucia Masters with a superb six under par 65 and, with Sergio Garcia losing the magic of last week, leads by two from England's Ross Fisher.
"Valderrama is the kind of course that suits me," Ramsay, third at the Castello Masters on Sunday 12, strokes behind Garcia, told reporters.
"It's a shot-maker's course. You need to manoeuvre the ball right to left or left to right, sometimes you need the low shot or the high one and I feel comfortable doing that.
"I worked out a good game plan with my caddie about how to play it in the wind and it's always nice to have a 65 around a classic course like this because it's had the Ryder Cup and so many great champions."
Out in the first group of the day, the former US Amateur champion went to the turn in a three under 32, then started for home birdie-eagle and picked up another stroke at the short 15th.
Ramsay's only mistake came when he took six on the 536-yard 17th, missing the green with his pitch over the water into the wind.
Fisher, down to 83rd in the world a year after making his Ryder Cup debut and without a top five finish all season, had seven birdies and 10 pars, but also a triple bogey seven.
That came on the eighth, at 350 yards the shortest par four on the Spanish course, after his drive hit a tree and went out of bounds.
Garcia threatened to be the story of the day again when he chipped in to match Ramsay's eagle on the 11th and reached four under, but in the end he had to settle for a one under 70.
Justin Rose, playing only his fourth event in Europe this year, had a 72 and defending champion Graeme McDowell a 73.
Nick Dougherty's nightmare time continued with a 13 over par 84 that put him last of the 96 players.
Dougherty has made only one of his last 28 halfway cuts going back to last November and has slumped from 46th in the world to 837th.
Ramsay's fellow Scot Stephen Gallacher shares third place with France's Gregory Havret on three under after a day when only four of the field broke 70.