Shubhankar Sharma said leading the WGC-Mexico Championship ahead of world number one Dustin Johnson, Jordan Spieth and Sergio Garcia is a "total dream come true".
The unheralded Indian golfer soared into a two-stroke lead following the second round in Mexico City on Friday.
The 21-year-old - a two-time winner on the European Tour this season - carded a five-under-par 66 to move clear of Masters champion Garcia, Xander Schauffele and Rafa Cabrera-Bello.
Defending champion Johnson is four strokes off the pace at the halfway stage of the exclusive event, while three-time major winner Spieth is two shots further back.
Asked if he had any surreal moments at the tournament, Sharma revelled in his lofty status, saying: "Every day. Even in the hotel, the gym, we see so many of these guys in the gym.
"Practising with all these good players on the range, [Jordan] Spieth was right behind me, and after a couple shots just stepped back and watched and then Dustin [Johnson] replaced him, so it's like I couldn't ask for anything better.
"It's a total dream come true," he added. "Everything has happened so fast for me. In the past four months, my life has totally changed. Obviously, the final destination for me is the PGA TOUR. That's always been my dream. Just playing well here this week will get my closer to my dream."
Garcia impressed as he moved within striking distance after 36 holes thanks to Friday's 65. The Spaniard was flawless, holing an eagle and four birdies at Club de Golf Chapultepec.
"It's the kind of golf course I like," Garcia said. "Valderrama is my favourite golf course, small greens. [TPC] Sawgrass, one of my favourite golf courses, small greens. I feel like my ball-striking can do most of the talking."
Former world number one Spieth posted a second-round 67 and the American star said: "You feel like you need to make a lot of birdies, but I believe [the winning score] will be somewhere around that again, around 14 under again."
Johnson shot a five-under-par 66, while he holed out for eagle on the par-four ninth hole.
"I have a lot of confidence going into the weekend," Johnson said.