He shares the lead with 17-year-old Jordan amateur Shergo Al Kurdi and England's Alex Belt after the opening round of the $75,000 Journey to Jordan #1.
On a difficult scoring day at a wind-swept Greg Norman-designed course at Ayla Golf Club in Jordan, the trio all carded two-under-par 70s.
Locke, who finished a celebrated amateur career last year and turned pro, qualified for the MENA Tour with three successive rounds of 71 in the Qualifying School B at the same venue, and went one better despite having to grind out the whole day.
“I am really surprised that two-under par is leading the tournament," said Locke, who qualified for the third-tier circuit with three successive 71s at the same venue.
"I did not play particularly well today but the conditions were very difficult, and I had to work hard to hang in there.”
The 21-year-old, who won the Silver Medal in the 2018 Open Championship in Carnoustie, is hoping for a big season in his second full campaign in the paid ranks.
“I have been struggling a bit with my short game here," he added. "But I managed myself well, hitting a lot of knock-down shots which I have grown up hitting on Scottish links. "Hopefully, I get calmer conditions in the morning tomorrow and capitalise on this round.”
England’s David Langley and Sweden’s Per Langfors were the only other players to come in with sub-par scores as they shot 71s in the season-opening event on the Arena-backed circuit.
Eleven players, including Scottish duo Scott Henry and Craig Ross, are tied for the sixth on 72.
Conor O'Neil is next best among the Caledonian contingent, followed by Ryan Lumsden (75) and Calum Fyfe (76).
Elsewhere, Amateur champion James Sugrue is handily-placed after the opening round of the African Amateur Stroke-Play Championship at Leopard Creek.
The Mallow man, who beat Euan Walker in the Amateur Championship final at Portmarnock last year, sits joint-fourth after carding a three-under 69.
As South African youngster Ryan van Velzen opened with a 64 to set a blistering pace, former Scottish Boys' champion Connor Wilson fared best among the Scots in the field with a 73, one better than Lewis Irvine.