Chile's Felipe Aguilar carded his best round on the European Tour for 17 months to take a two-shot lead on first day of the Lyoness Open in Austria.
The world No. 399's seven-under-par 65 -- his best effort since the Joburg Open in January 2016 -- took him clear of the chasing pack at the Diamond Country Club in Atzenbrugg outside Vienna.
South Africa's Jaco van Zyl, Sweden's Johan Carlsson and England's former Walker Cup winner Ashley Chesters are in joint second with two other Englishmen, Graeme Storm and Oliver Wilson, a further shot behind in a tie for fifth with France's Joel Stalter.
No-one could match the form of the 42-year-old Aguilar, whose last win came in 2014, on the front nine as he raced to five under after just seven holes and a birdie at the 10th put him in the outright lead only for him to bogey the next.
However, he responded with birdies at 13 and 14 but failed to capitalise on the back-to-back par 5's and the par-3 last but still had enough to pass clubhouse leaders Zyl and Carlsson, later joined by Chesters.
Van Zyl, still searching for his maiden European Tour victory after five runners-up finishes, carded two birdies on the front nine and three after the turn.
A number of players out on the course briefly joined him at the top of the leaderboard but none other than Carlsson of the morning starters could maintain their position.
The Swede had two bogeys and seven birdies, the last at the 18th giving him a share of the lead.
Home favourite and 2012 champion Bernd Wiesberger, who admitted pre-tournament he has eyes on next week's US Open, suffered from a loss of concentration having taken a share of the early lead.
A run of five birdies in six holes from the 15th, having started on the back nine, was ruined by a lost ball off the tee at the fourth and a double-bogey on the eighth after a poor greenside bunker shot saw the Austrian, one of only two players innthe world's top 100 in the field, finish two under.
Luiten fared even worse with a one-over 73 which included an eagle, three birdies and a double-bogey.