The 32-year-old Swede, famous as much for his colourful dress sense as his golf, shot a superb 64 to jump to the top of leaderboard at 11 under par and claim pole position for the pounds 120,000 first prize.
Victory at the Sporting Club this weekend would guarantee his place in the European side to defend the trophy in the United States in September, although even a top-10 finish should be enough to ensure he is a definite member of Mark James' side.
"That would be really nice because I would then be able to relax," said Sandelin, currently fifth in the points standings and who had eight birdies in his round with matching halves of 32 on the Nick Faldo-designed course. "The Ryder Cup is a great team event and a great chance to play against the best players in the world. Golf is an individual game and we play so few team events.
"There will be nerves of course, but I get nervous in the last round of ordinary tournaments and hopefully my game is good enough now to handle the pressure. I had a very bad time when I played in America a couple of years ago, so it will be nice to go back as one of the 12 best golfers in Europe."
Sandelin had a 69 in the first round and began yesterday seven shots behind England's Gary Evans, who had broken the course record with a 10-under-par 62. However, with Evans failing to reproduce anything like that kind of form, the Swede soon closed the gap and moved into the outright lead with four consecutive birdies in the middle of his back nine.