Local favourites Nacho Elvira and Jon Rahm joined Paul Dunne at the top of the leaderboard as the final round of the Open de España got into full swing at Centro Nacional de Golf.
Ireland's Dunne started the day with a one-shot lead but he parred his first three holes, allowing the Spanish pair to join him at 17 under after early gains.
South African George Coetzee was then the clubhouse leader at 16 under, a shot clear of Australian Brett Rumford.
World Number Four Rahm has seven National Championship victories as an amateur at various age levels but this would be his first professional victory on home soil.
It would also make him the third fastest player to three European Tour wins in terms of events played after last season's two Rolex Series triumphs in Ireland and Dubai.
Dunne claimed his maiden title at last season's British Masters supported by Sky Sports, while Madrid native Elvira's best finish on the European Tour was a play-off loss at the 2016 Trophée Hassan II, although he does have four Challenge Tour wins.
It was clear from the off that low scores were available with first Sébastien Gros and then Julien Guerrier firing rounds of 64 to set the clubhouse target initially at 13 under and then 14 under.
Coetzee then equalled the lowest round of the week with a 63 that got him within a shot of Dunne before the leader had even completed his first hole.
The Tshwane Open champion birdied the first, second, fifth, sixth and eighth to turn in 31 and then eagled the tenth. He birdied the 13th and last to get to 16 under alongside Elvira and he was soon joined by Rahm.
The 23 year old played a beautiful chip at the first to set up a birdie and when he hit a huge drive on the second to set up another gain, he was in a share of the lead.
Elvira also birdied the par five first and there was very quickly a three-way tie for the lead at 17 under.
Dunne started his round with three pars while Rahm did well to save par on the fourth after going a long way left off the tee.
Rumford birdied the fifth to sit two off the lead, while Jorge Campillo made a birdie-birdie-birdie start but bogeyed the fourth to sit 14 under after five holes.
Rak-hyun Cho and Yusaku Miyazato were in the clubhouse at 13 under alongside Gros, with Henric Sturehed, Andy Sullivan and Marc Warren also at that mark.