|Wells Fargo Championship second-round leaderboard|
|-11 J Dufner (US); -10 J Dahmen (US), M Homa (US); -6 R McIlroy (NI), P Reed (US) ; -5 J Rose (Eng), S Power (Ire), J Day (Aus), P Perez (US)|
|Selected others: -4 M Laird (Sco); -2 P Casey (Eng); +5 P Mickelson (US); +7 D Willett (Eng); +8 P Harrington (Ire)|
Rory McIlroy believes he remains a leading contender at the Wells Fargo Championship despite falling five shots off the lead at the halfway stage.
World number four McIlroy, joint leader after an opening 66, dropped three shots on the final two par-fours and had to settle for a one-under-par 70.
Despite the gap, McIlroy is optimistic about his chances at Quail Hollow.
"I am still right there, but I get off to a good start on Saturday," the Northern Irishman said on pgatour.com.
McIlroy is six under overall and in a share for fourth place, five shots adrift of pacesetter Jason Dufner.
McIlroy had carded five birdies and one bogey in his opening 16 holes on Friday, but much of that good work was undone at the end.
On the short eighth - his penultimate hole of the day after starting on the 10th - McIlroy found a bunker off the tee and, despite being only 55 yards to the green, conspired to take another five shots as he recorded a double-bogey.
The four-time major champion, looking to celebrate his 30th birthday this weekend by winning this event for a third time, also bogeyed his closing hole.
McIlroy was better off the tee on Friday than he was on Thursday but ended up scoring higher.
"Golf. It's a funny game," added McIlroy.
"I stood up here on Thursday night talking about how I got the most out of it, and today was the complete opposite. I turned a 66 into a 70."
American Dufner followed up his opening 68 with a superb eight-under-par 63 that included an eagle, seven birdies and just the one dropped shot as he moved to 11 under.
Max Homa also signed for a 63 - his blemish-free - to sit alongside Joel Dahmen in joint second place on 10 under.
Dahmen, who was overnight leader alongside McIlroy, shot a second successive 66.
Patrick Reed (69) is on six under with McIlroy, while England's Justin Rose (67) and Ireland's Seamus Power (68) are among a group of four players a further shot back.