Ross Fisher carded a second round of 4-under 68 to claim a one-shot lead at the halfway stage of the Alfred Dunhill Links Championship on Friday.
Fisher carded seven birdies and three bogeys on the Old Course at St. Andrews, one of the three venues used for the pro-am event.
At 11 under par, the Englishman enjoyed a one-shot lead over Sweden's Joakim Lagergren, whose 68 came at Kingsbarns, where first-round leader Alex Noren shot a 71 to finish 9 under.
Thomas Pieters was five shots off the pace after a 68 at Kingsbarns, but was left to regret a double bogey on the 17th after six birdies in the previous 16 holes.
"Just a shame to finish with a double but I was going along nicely and making a few putts," said Pieters, who claimed a record four points from five matches on his Ryder Cup debut at Hazeltine. "That three-putt on 17 hurt but I am looking forward to playing St Andrews tomorrow.
"I didn't play a practice round on it because I was too tired, but I know the course. I've been here two or three times, so really looking forward to playing the Old Course."
Martin Kaymer was a shot behind Pieters after his own 68 at Kingsbarns, but Lee Westwood was propping up the leaderboard on 13 over par after slumping to an 82 at the same venue.
Masters champion Danny Willett and English compatriot Matt Fitzpatrick face a battle to make the 54-hole cut after rounds of 73 left them 2 and 6 over par respectively.