Marc Warren and Paul Dunne finished their first rounds with a flourish to lead the Open de Espana, while Jon Rahm and amateur Victor Pastor are just one shot off the pace in their homeland.
Warren, without a victory on the European Tour since 2014, birdied five of the last seven holes to start with a six-under 66 at Centro Nacional de Golf on Thursday.
The 37-year-old has failed to finish in the top 50 this year, but made just one bogey at the fourth and raised his game on the back nine to take over at the top of the leaderboard in Madrid.
Dunne matched Warren's opening round when he went out later in the day, the Irishman conjuring up an eagle at 18 after making three of his five birdies on the back nine.
Rahm arrived on home soil buoyed by a fourth-place finish in the Masters last weekend - his best showing in a major - and put himself firmly in contention to claim a first professional title in Spain.
The world number four hit the turn in 34 after starting on the back nine, an eagle three at 18 putting a spring in his step following his solitary dropped shot at the previous hole.
Rahm - who spent two years practicing on the course earlier in his career - made further gains at the third, fifth and seventh in a strong start to his challenge.
Pastor, 113th in the Amateur Golf Ranking, started with an eagle and came up with five birdies before a bogey at the last cost him a share of the lead.
Jason Norris, Jonathan Thomson, Julien Guerrier, Erik van Rooyen and Matthias Schwab are also just a solitary shot behind the leading duo on five under along with Alexander Bjork, Henric Sturehed, Callum Shinkwin and Aaron Rai.
Andrew Johnston, 2016 winner and defending champion as the tournament was not on the European Tour schedule last year, is among nine players a further stroke back.
22. September 2018
|Kluivert to get Roma chance as Di Francesco demands focus|
|Robinson optimistic injured Cronk will be fit for Grand Final|
|WATCH: Ferguson given immense ovation on Old Trafford return|
|Three in a row for Lorenzo at Aragon|
|Warner makes 155 on Australian grade cricket return|
|Pain-free Kyrie Irving ready to lead Celtics to NBA title|
|Firmino returns as Shaqiri gets first league start|
|Fulham 1 Watford 1: Mitrovic shines late to spoil Gray´s day|
|Ronaldo vows to lose weight and assist training after Real Valladolid purchase|
|Patriots WR Josh Gordon listed as questionable to face Lions|
|500th goal was crucial to my new book - Ibrahimovic|
|Roosters survive Cronk injury to hold off Souths and reach Grand Final|
|Murray announces intention to end season early|
|I want to play right-back for England - Walker|
|I would beat Bolt for speed on the pitch, claims Traore|
|Ferguson returns to Old Trafford for Manchester United v Wolves|
|Walker ´hurt´ by Pochettino claims over Tottenham exit|
|Douglas Costa has paid his fine for Sassuolo spitting incident – Allegri|
|Djokovic: Sock gave me karma back for hitting Federer|
|Anthony Joshua v Alexander Povetkin: Tale of the tape|
|Wang thrashes Putintseva to win Guangzhou title|
|There is no problem with Cavani - Tuchel silences rumours of PSG rift|
|Wilder & Fury sign contracts for December 1 bout|
|Neymar is the Kim Kardashian of football, claims Barton|
|We did not want to sell him - Perez insists Madrid got ´highest value´ for Ronaldo|
|Osaka continues run, Pliskova awaits in Tokyo final|
|Cardinals keep pace in wildcard race with win over Giants|
|Djokovic hits Federer, pair lose in doubles at Laver Cup|
|Nowitzki likely to come off bench for Mavericks in 21st season|
|Red Wings´ Green battling ´virus that attacked his liver´|
|They said I couldn´t score goals – Ibrahimovic hits back at early critics|
|Slater charged, set to miss Grand Final|
|Rose not changing approach alongside Woods|
|Woods ready to ´hang in there´ at East Lake|
|Shaqiri´s time will come at Liverpool – Klopp|
|Richarlison: I used to copy some of Neymar´s haircuts|
|Brady says Gordon is ´really eager to get in there´ despite limited practice|
|NBA changes clock-reset, ´clear path´ foul rules|
|Tigers´ Martinez will play final game on Saturday before retiring|
|Sanchez to start for Man United – Mourinho|
|Speight saves Ulster in thrilling Cheetahs draw|
|Simmonds at the double as Chiefs stay perfect|
|Woods, Rose share Tour Championship lead|
|Ice-cool Shoaib denies Afghanistan in final over|
|CAF Champions League Review: Wydad Casablanca out as TP Mazembe pay penalty|
21. September 2018
|Eden inspires rout as Castleford book Wigan semi-final|
|Thiem & Wawrinka reach St. Petersburg semi-finals|
|No change to Aguero selection despite new contract, warns Guardiola|
|Woods and Rose share Tour Championship lead|
|Wigan Athletic 1 Bristol City 0: Three on the trot for improving Latics|
|Josh Rosen will play ´when time is right,´ Cardinals GM says|
|Eagles RBs Ajayi & Sproles out Sunday v Colts|
|Ronaldo looking forward after Champions League red card - Alex Sandro|
|Rangers fire manager Jeff Banister after four seasons|
|Inter captain Icardi can improve - Spalletti|
|Jadeja and Rohit shine as India maintain 100 per cent record|
|Fisher shares lead in Vilamoura after record-breaking 59|
|Messi the best I´ve seen - Lamela|
|Silva demands end to Gomes ´rumours´ and targets early October return|
|Milner over Pogba, says Souness|
|Brazil call up Malcom, drop Thiago Silva and Willian|
|Denly thought Test chance may never come|
|Benitez tells FA to examine Zaha red card comments|
|Bjorn unsure of future after Ryder Cup|
|Tebas still optimistic over Girona-Barcelona in Miami despite RFEF setback|
|Emery promises more chances for frustrated Leno|
|Cahill considering Chelsea departure in January|
|Kaepernick to receive Harvard´s highest honour in African, African-American studies|
|Defending champion Ostapenko dumped out of Korea Open|
|Mourinho is an inspiration - Nuno|