MEMPHIS, Tenn. — Robert Karlsson keeps playing better and better at TPC Southwind. The Swede could be on track for his first PGA Tour title if he keeps it up.
    Karlsson is focused only on his next round.
    "That's a question we'll discuss when it happens," Karlsson said.
    Karlsson shot a 5-under 65 on Friday to take a three-stroke lead after the second round of the St. Jude Classic. He started a stroke behind first-round leader David Mathis and carded six birdies and a bogey to reach 9 under. Karlsson, who lost here a year ago in a playoff with Lee Westwood, has played his first six career rounds at the course under par with this his lowest score yet.
    "It's actually a bonus that I did well here last year," said Karlsson, who is ranked 23rd in the world and has 11 career European Tour titles.
    "But this year is a new year, and even now most likely going to be in the lead after two days makes no difference. We've come halfway, and who knows. I might finish 55th. You never know. You've got to keep going, especially on punishing golf courses like this."
    Colt Knost (68) and Keegan Bradley (67) were tied for second. Bradley, the Byron Nelson Championship winner two weeks ago, is among a few who can earn a spot last week in the U.S. Open at Congressional by winning his second tour event since the last Open.
    John Merrick (69) was 5 under, and Fredrik Jacobson (65) and Harrison Frazar (65) were another stroke back. Brandt Snedeker, The Heritage winner in April, shot a 66 to top the group at 3 under that included Mathis (72). With 83 making the cut at 2 over, David Toms (5 over) and Sergio Garcia (7 over) were among those who made an early departure for Congressional.
    Nobody beat Karlsson in over 72 holes here in 2010, and he credits the lessons learned on his first practice round here a year ago to avoid hitting into the rough on this 7,239-yard course as much as possible to better set up shots into the greens. Temperatures in the high 90s the past couple weeks have firmed up the Champion Bermuda greens.
    "It can be better to have an 8-iron from the fairway or a 7-iron from the fairway instead of a wedge from the rough," Karlsson said. "The greens are firm, and the rough is really, really brutal to control the golf ball out of. You can hit it. you can hit it really far, very, very far because you can get some vicious flyers."
    Starting at 4 under and teeing off on No. 10, Karlsson birdied his second hole and finished the back side with birdies on three of the final four holes. He hit an 8-iron to 8 feet on the par-3 11th to set up his first birdie. He saved par on Nos. 12-14 and then hit a wedge from 106 yards to 7 feet to take advantage of a front pin position on the par-4 15th to start his birdie string.
    Karlsson found the rough with his tee shot on the par-5 16th but he recovered by hitting a wedge from 124 to 5 feet for a second straight birdie. He stuck a 7-iron from 175 yards to 4 feet on the par-4 18th to reach 8 under.
    "I hit a bunch of good iron shots. It was nice obviously to get it going. As you said, it's not an easy golf course. You just don't walk out there and shoot 68, 67. It's always nice to get off to a good start. I played very well on m back nine as well. Gave myself a bunch of chances, and it was good," Karlsson said.
    He made the turn and birdied the par-4 first after hitting his second shot within 4 feet of the pin despite being 124 yards out in the primary rough. When Karlsson rolled in a 14-footer on No. 6 for birdie, he became the first player to reach double digits below par at 10 under.
    Karlsson dropped a shot with his lone bogey of the round and just his second this week when he three-putted from 34 feet on the par-3 eighth.
    Bradley admitted to being a bit tired at Memorial following his win at the Byron Nelson Championship. He missed the cut, and he said he and his caddie got back to doing what worked in Texas. He had a bogey-free round with three birdies.
    "Never had to do all the media that I had to do. Obligations that a winner has to go through, which I'm so happy I had to go through it, but it took me a little bit by surprise. But feel good and feel rested now," Keegan said.
    Knost is among the Nationwide Tour graduates from 2010 playing well here. The SMU graduate who turned pro in 2007 has made the cut in eight of his 16 PGA events this year and in good position for his best finish yet.
    "Kind of been struggling coming into this event, but you know I just kind of took a new mindset this week and just got off to a great start yesterday and played solid again today," Knost said.
    DIVOTS: Michael Bradley eagled the par-5 16th when he holed out from 66 feet from a greenside bunker. ... Kip Henley didn't miss out on a big check by deciding to play here. Usually Brian Gay's caddie, he chose to play instead of work after earning a spot by winning a Tennessee tournament last August. Henley missed the cut at 20 over, while Gay also missed the cut after a 2 over. ... Patrick Reed's pro debut after helping Augusta State repeat as NCAA champs didn't go too well. He missed the cut at 6 over.