Kristian Krogh Johannessen made a storming start at the Open de Espana, where defending champion Jon Rahm was among the home favourites to begin strongly.
Norwegian Johannessen, starting at the 10th hole, birdied four of his last six holes at the Club de Campo Villa de Madrid to sign for an outstanding eight-under-par 63.
Had preferred lies not been in play, Johannessen's score would have entered the history books as the lowest opening round in tournament history and matched the course record.
Still, Johannessen – who made an eagle two at the 15th and had just one bogey at the following hole – will a take a two-shot lead into round two.
"It was a good round," Johannessen, who missed the first nine cuts of his rookie year after graduating from qualifying school last season, told the European Tour's website.
"I didn't hit it perfectly but hit it in the right spots, even when I missed and I holed some good putts.
"I'm out there having fun and playing smart. It's a tricky course but I've got a friend on the bag this week and we're having fun out there.
"If you get stressed you start easily making mistakes. I just need to keep cool and play my own game."
Spain's Adri Arnaus is the highest-placed home player. Also starting at the 10th, he was six under by the turn before a bogey at the second hole slightly derailed his progress.
A birdie at his last hole meant Arnaus was six under and one shot ahead of a cluster of six players, which included playing partner and compatriot Rafa Cabrera Bello.
Rahm was also among that group, the 2018 victor's card showing six birdies and just a solitary dropped shot.