SHANGHAI — Dustin Johnson overpowered Sheshan International on Friday with a stunning display off the tee that carried him to 10 birdies, a share of the course record with a 9-under 63 and a five-shot lead going into the weekend at the HSBC Champions.


“I’m driving it really good,” said Johnson, and while that didn’t provide much insight, he really didn’t need to say much more.


The 29-year-old American, who was 1-over after his opening nine holes of this World Golf Championship, hammered a drive on the par-5 second hole and has been on a roll ever since. He is 13-under over his last 27 holes.


Johnson became the sixth player to shoot 63 at Sheshan, and the first since Martin Kaymer in the final round two years ago.


He was at 12-under 132.


Rory McIlroy, who started the second round with a two-shot lead, reached 10-under at the turn and couldn’t keep up. McIlroy hit into the same fairway bunker on No. 11 as he did on Thursday and made bogey, but he didn’t have many birdie chances the rest of the way and had to settle for a 72.


McIlroy was at 7-under 137 with Boo Weekley (67) and former Masters champion Bubba Watson (69).


With a wedge in his hand on the par-5 14th, McIlroy went just over the green and had to hit a delicate chip to save par. He drove into the tiny pot bunker left of the green on the par-4 16th and took two shots to get out. And on the par-5 18th, his second shot found the water, leading to bogey.


“I just hit a couple of bad shots, and then I guess I let it affect me a little bit, and then I started to doubt myself sometimes,” McIlroy said. “I didn’t hit a lot of quality shots on the back nine.”


Johnson hardly missed. He only hit eight of 14 fairways, but several of those were in the first cut of rough, and two of them counted as missed fairways because he was trying to drive the green on the par 4s. At the seventh, his tee shot was just short of the bunker in front of the green, leading to an easy up-and-down for birdie. On the 16th, he hit 3-iron just short of the green in a drain, took a free drop and chipped to 3 feet for birdie.


“What’s possible for an athlete like him who just rips it, that’s not what’s possible for the rest of us sometimes,” said Graeme McDowell, who had another 69 playing in Johnson’s group and was six shots behind. “He’s an impressive guy. When he’s in the mood and when he’s on form, he’s pretty prolific.”


There was a big crowd behind in case Johnson slips up on the weekend.


Ernie Els, Sergio Garcia, BMW Masters winner Gonzalo Fernandez-Castano and Ian Poulter were among those at 6-under 138. Phil Mickelson, trying to recover from his quadruple bogey-bogey finish to the opening round, had a 68 and was seven shots behind.


Couples leads for the Charles Schwab Cup

SAN FRANCISCO — Fred Couples took the second-round lead Friday in the Charles Schwab Cup Championship, shooting his second straight 6-under 65 in the Champions Tour’s season-ending event.


Winless this season with four runner-up finishes, Couples had a bogey-free round at TPC Harding Park.


“This is a big event,” Couples said. “These are the best players on the tour and I want to win. I’m certainly not playing any better because I want to win. I want to win at Birmingham, Seattle, Chicago, Newport and everywhere else I finished second.”


First-round leader Peter Senior bogeyed the 18th for a 69 to fall two strokes back.


“I didn’t do much wrong,” Senior said. “I didn’t get away with anything but I think I’m in a good position. I had a heap of chances early in the round that I didn’t convert.”


Bart Bryant was third at 8 under after a 66. Bernhard Langer was another stroke back after a 68.


Charles Schwab Cup points leader Kenny Perry had a 71 to remain 3 under. Langer is the only player with a chance to overtake Perry. Even Langer wins the tournament, Perry would take the season title and $1 million annuity if he finishes fifth or better.


Fred Funk aced the par-3 eighth hole with a 4-iron, but bogeyed four of his next seven holes and finished with his second straight 70.


Couples took the lead when he parred the eighth hole and Senior had a bogey. Couples birdied Nos. 9 and 10 and led by three strokes.


“I had another good round and hit the ball well,” Couples said. “When I hit pretty good irons I made the birdies. When you’re near the lead, playing fast is a bonus.”


Couples, who last won at the Senior British Open in July 2012, continues to deal with neck and back pain and said he’ll consult a doctor Monday to find the cause.


“There’s something going on,” Couples said. “It’s just not comfortable. It’s doable. Sometimes when I turn I snag it. It’s more at night when I’m lying down. My back hurts and I don’t sleep much. I wouldn’t be playing if it hurt to swing.”


Couples learned how to play golf at a public course in Seattle, which is why he feels comfortable at Harding Park.


“This is one of my all-time favorite courses,” Couples said. “That helps me. As far as length, if I hit every fairway, I’ll have an advantage all right, over my normal game.”


Senior, who spent most of his career on the PGA Tour of Australasia, has yet to win on American soil.


“If you play well enough, you’re going to do it,” Senior said. “Inside me I know I’m good enough to win tournaments and I’ll go out there with that on the weekend.”