Irving:The second round of the Byron Nelson was played at both the Cottonwood Valley and the TPC Four Seasons golf courses on Friday in Irving, Texas.
First round leader O'Hair made the turn at three-under but pulled a stroke back with a birdie on 13.
O'Hair was deep in the trees after his wayward tee shot at 14th and was forced to chip back onto the fairway before a nice par save.
After a pitch shot to 20 feet, his putt looked like it was about to stop rolling, then it took one more turn and dropped into the cup - to the relief of the 24-year-old.
He gave another stroke back at 15 to finish at 1-under for the round and was 6-under par heading into the weekend.
Phil Mickelson and Vijay Singh, the only top-10 golfers in the world ranking playing this week, were in the same group at Cottonwood Valley on Friday.
Seventh-ranked Singh was only inches away from a hole-in-one of the 12th and the Fijian made birdies on four of the last seven holes to finish at 3-under par Friday for a two round total of 4-under par 136.
World number four Mickelson, in his first tournament since the Masters, missed an easy birdie putt on the 11th which summed up his frustrating round.
He carded three bogeys on the final seven holes during an even-par round of 70. Mickelson was 1-under par over two rounds.
Mike Weir hit a solid tee shot on the 13th and carded a two-under par round on Friday at the TPC Four Seasons. The former Masters champion was also two-under for the tournament.
Jason Gore nailed a long range birdie attempt on the 15th and was 4-under par despite running into trouble with a double-bogey on the 17th hole at the TPC Four Seasons. Gore made seven birdies on the day.
Donald, who has four top-10 finishes this season, holed a 25-foot chip for birdie at the 426-yard (390 metres) 12th hole to go to seven-under par.
After giving back a stroke on the par-4 14th hole, Donald took over sole possession of the lead with a 43-foot chip from the edge of the green at the 196-yard (180 metres) 17th.