The Spaniard is 3-under and holds a one-stroke lead over Tiger Woods, Lee Westwood, Henrik Stenson and Dustin Johnson.
"Been playing very well. Feeling solid and consistent on the golf course," Jimenez said after a second-round 71. "This condition is tough. The golf course is very hard. Some of the positions, the pin positions, they are very tough."
Evidence of just how tough Muirfield is playing is right on the leaderboard, as just nine golfers found themselves under par heading into the weekend.
Jimenez's secret? Don't make bogeys.
"And then, of course, even when you play well, you're going to miss some greens, you're going to miss some fairways," Jimenez said. "As I said before, sometimes it's not about to make too many birdies, it's about not to make bogeys. To play the golf course in this condition, that's one of the keys."
Another key, perhaps, is just how loose Jimenez is -- and that's not in reference to his pre-round stretching routine. Jimenez spoke time and again about how happy he is to be playing golf, and that there's no place he'd rather be.
That's hard to argue with.
"I feel relaxed. And I tell you, I love what I'm doing. I play golf," Jimenez said. "I do this for a living. And I've kept doing the same thing for 25 years. Probably sometime you say if I think maybe it's too many years, but you're wrong. It's the only thing I like to do in my life."
And when asked how a 49-year-old was leading this year's Open, Jimenez scoffed at the notion that his age is a factor -- even though he'd be the oldest man to win a major.
"Why? I have not the right to do it?" Jimenez said. "Only the young people can do it?"
Then, in explaining his craft, he doled out some life advice.
"Enjoy yourself what you do in life," Jimenez said. "That's what I'm doing."