Jon Rahm was surprised to find himself in contention after an illness-hit build-up to the 2024 acciona Open de España presented by Madrid.
A birdie-birdie finish gave the three-time champion a three-under-par first round of 68 at Club de Campo Villa de Madrid, good enough for a share of fifth and three shots behind leader Angel Hidalgo.
Rahm said: "I was telling somebody before the round, I think it was my family, just flying in yesterday afternoon, not having touched a club in a while, and between being sick and hospital beds, I was like, 'with the wind forecast, if I could somehow break 75, I'll be happy.
"I kept putting it in play for the most part and giving myself good looks, made really good par putts on six and 11 that saved the round. Had a great finish and I find myself with a great score that is rather, I would say, unexpected."
Rahm - winner of his home Open in 2018, 2019 and 2022, the latter two at this venue - responded to a bogey at the third by reaching the next in two and going within an inch of holing the eagle putt that followed.
He settled for birdie and added another at the eighth to get out in under par, before holing from 20 feet for a further gain at the 13th.
An uncharacteristically poor chip at the 16th led to a dropped shot but again, he bounced back - first with a 27-foot putt at the 17th then a perfect drive, chip and putt at the last.
After following both his bogeys with birdies, he joked: "I wish I could do it on purpose. Luckily I only had two bogeys today.
"I think the (birdie) on 17 was very important because you make a bogey after what I felt like was a good swing off the tee, and then you get to a difficult hole - it's 195 yards with the crosswind, into the wind, and the green, it's tiny, it looks like a thumbtack.
"There's nowhere to miss it where it's easy, and to hit a good shot and make the putt was huge."