Angel Hidalgo held off three-time champion Jon Rahm in a play-off to win the 2024 acciona Open de España presented by Madrid.
The pair had gone head-to-head in an all-Spanish final group with David Puig, with Rahm's birdie-birdie finish leaving them tied at 14 under par.
Both players birdied the first extra hole but after Rahm's chip slipped past second time, Hidalgo holed a two-foot putt for victory.
He said: "Two or three years ago, I was in the first tee, in the trees, supporting Jon - without playing, I just come here to Madrid to see the tournament.
"To be here and win the tournament is unreal. Oh, my gosh, it's amazing."
It was the first all-Spanish final group at the national Open since 2019, when Rahm won comfortably ahead of Rafa Cabrero Bello and Samuel Del Val.
It was closer this time, right from the off as Hidalgo's two-shot overnight advantage was wiped out at the first hole - he missed a three-foot putt and made bogey while Rahm, also champion in 2018 and 2022, started with a birdie, as did Puig to lie one shot behind.
Hidalgo responded impressively with a birdie at the second, with a superb approach from a fairway bunker, while Puig's 15-foot putt took him level with Rahm - who then bogeyed the third.
Puig shared the lead after a brilliant third birdie in the first four holes, though Hidalgo would have been happy to escape with par after a wayward approach. Rahm's three-putt par left him two behind.
Consecutive dropped shots for Hidalgo at the fifth and sixth left Puig two clear, which became three with a birdie at the par-five seventh.
Jens Fahrbring had eagled the seventh and was up to 10 under for the first time, level with Rahm who bogeyed the same hole.
Puig bogeyed the eighth, his approach spinning back to the lower tier of the green, and his playing partners both responded with birdies.
Hidalgo birdied the next as well to go to the turn level, Rahm following him in to move one off the lead as Puig salvaged any further damage with a sublime up and down for par.
Rahm's birdie at the 10th left all three players level, before Puig sent his tee shot way through the 11th green - he salvaged a bogey but dropped one off the lead.
Hidalgo hit the front on his own at the 13th, where a bogey for Puig and a double for Rahm dropped both players to 11 under - leaving Fahrbring suddenly second outright after three consecutive birdies.
The Swede immediately bogeyed the 15th while Hidalgo sent his second shot to the 14th off line to the right, where it struck a tree and settled short of the huge greenside bunker.
Rahm made birdie - and went within inches of an eagle - but Hidalgo matched him with an astonishing up-and-down after a skyscraping flop over the sand.
That follow through...😂@Angel_Hidalgo7 sets up birdie in style 🔥#AccionaOpen pic.twitter.com/kjjxZtfDqd
— DP World Tour (@DPWorldTour) September 29, 2024
Rahm's 19-foot putt to birdie the 17th cut the margin to one and after he also birdied the last, Hidalgo's putt stayed right of the hole to set up a play-off.
With the par-four easily driveable, Hidalgo found the front of the green while Rahm was able to chip close, with both making birdie.
Rahm's tee-shot second time headed off towards the grandstand and after he chipped through the green, Hidalgo could nurse his ball close before holing a two-foot winning putt.
He said: "I was pretty relaxed all day, even the first tee, I don't know why. Even when I missed the short putt (at the first) - or this one, hole 72 - I was not discouraged.
"On the eighth tee, I thought David Puig is going to win the tournament by eight because he was hitting amazing, and Jon and myself made a few mistakes.
"That's amazing. That's for everyone that was there and believed in me, and yeah, my team, my family, especially my caddie, he's my best friend.
"I called him last year, I was struggling a little, and I called him and he stopped playing to carry my bag.
"And my grandpa yesterday was 80 years - well, he passed away a few years ago, but yesterday was his birthday.
"My best friend Paco and coach Jordi and my parents travelled this morning by train to be here for the tournament. I wish my brother was here but I will make a video call now - probably he cries more than me, knowing him."
Rahm paid tribute to Hidalgo and hailed the impact of Sunday's finale on Spanish golf.
"May he enjoy it," he said. "Winning at home, winning a Spanish Open with all the support that there has been. You could tell how much he felt it and how important it was for him.
"What happened today helps. Having a final like this, no matter who wins, helps those kids who were watching here or on TV to want to try playing golf to experience moments like today’s."
Puig finished in a large group at 10 under with Fahrbring, English pair Tommy Fleetwood and Joe Dean, Scotland's Grant Forrest - who shot 64 on Sunday - and American Sean Crocker.
South Africa's Jayden Schaper was on his own in ninth at nine under with Alfredo Garcia-Heredia, Patrick Reed and Tyrrell Hatton sharing tenth.