When Russell Knox first contested the Wells Fargo Championship three years ago he was, by his own admission, an unknown rookie struggling to find his feet on the PGA Tour.

Knox had arrived at the Quail Hollow club in suburban Charlotte having missed the cut in six of his opening nine events of his maiden campaign on the world's strongest tour.

Three years and 66 events later, the Inverness exile has put himself in contention for a maiden PGA Tour victory with an eye-catching pair of 69s for a six-under 138 heading into the weekend.

"I was just checking when I was last in Charlotte and I shot rounds of 77 and 73 and really I wasn't that interested as I was on a poor run but coming back this year I just expect more of myself now," said Knox, who lost out in a play-off for the Honda Classic last season. "I am a lot more mature both personally and in terms of my golf but then some days you do feel more relaxed on the course and that's been a key these two days. I've just had this attitude of hit it, find it and hit it again whereas other days it can be very frustrating."

Among the other early finishers was Rory McIlroy, who moved menacingly into the title hunt with a 67 which hoisted him onto a 137 tally. The 26-year-old, seeking a second PGA Tour win in three weeks ahead of his defence of the BMW PGA Championship at Wentworth next week, won his maiden PGA Tour title here at Quail Hollow in 2010. A lot has happened since then. "Everything has changed, I am a much better player and my stature in the game is much higher and I feel like when I am on the leaderboard my name carries a little bit more weight," said the world No 1.

On the European Tour, meanwhile, the aptly-named Edouard Espana claimed the halfway lead in the Open de Espana as defending champion Miguel Angel Jimenez failed to make the most of a record-equalling hole-in-one. Frenchman Espana overcame strong winds which sent scores soaring in the afternoon to card a three-under 69 for a seven-under 137 and a one shot lead over Argentina's Ricardo Gonzalez. Jimenez had been four under after following birdies on the second and fifth with his ninth European Tour ace - equalling the record of Colin Montgomerie - on the eighth, but came home in 39 to card a 71 and finish one under. The 51-year-old at least had the consolation of winning 288 bottles of beer for his hole-in-one on the eighth, which came when his six-iron pitched around 15 feet short of the pin and rolled in.

Paul Lawrie was sitting in a share of 16th on 143 after a 73 while Richie Ramsay and Scott Jamieson (both 147s) were the only other Scots to make the cut.