Duval followed an opening 64 at Cottonwood Valley with a 65 at the TPC Las Colinas to earn a share of the 36-hole lead with Scott Verplank.
Verplank, also playing Las Colinas, shot a 3-under-par 67 to move to 11-under for the tournament.
Robert Damron birdied two of his final three holes to get within one of the lead at 10-under. Damrons 64 at Las Colinas matched the score recorded by Vijay Singh at Cottonwood Valley. Singh is just two off the pace at 9-under-par.
1997 Nelson champion Tiger Woods is five shots behind the leaders at 6-under following a 2-under-par 68 at Las Colinas. Woods, seeking his fourth consecutive PGA Tour victory, birdied his first hole Friday, but played his final seven holes in 1-over.
I didnt hit that many good putts today, said Woods, who took 32 putts in the second round. It was nice just to get it under par.
Im driving the ball great, hitting good irons, just not putting. Ill get a little practice in and it should be fine tomorrow.
Verplank struggled with the flatstick, as well.
Coming off a 23-putt 62 at Cottonwood Valley, Verplank needed five more swipes at Las Colinas on Friday.
Still, Verplank, a standard bearer at this event in his formative years, was pleased with his round. Hes well aware of the trappings that await players after shooting a low score.
If you go out there and you expect the same things to happen the next day as it did the first day, then, yeah, youre going to struggle with it, Verplank said. But I think after a while, you kind of realize that each day is different and you feel different.
Verplank started his day with a yanked tee shot at the par-4 1st, which led to his first bogey of the tournament.
However, he responded by collecting five birdies to just one bogey over his final 17 holes.
Playing in the group behind Verplank, Duval birdied his first hole, and then added six more to his card.
Despite a pair of bogeys, Duval was pleased with his round; and more so, pleased with his outlook ' both mental and physical.
Fighting back and wrist injuries over the past 18 months, Duval said he finally feels healthy.
Condition has led to contention.
Duval finished runner-up to Woods in this years Masters Tournament after missing five weeks due to tendinitis in his right wrist.
Now that he temporarily has his physical woes behind him, Duval is ready to ascend from his position as the seventh-ranked golfer in the world.
I certainly want to start winning golf tournaments again, said Duval, who is winless since the 2000 Buick Challenge. I feel like Im back in that position where I can.
I feel like Im at a point where I can just go play again and start winning golf tournaments again.
Duvals second-round 65 wasnt the low score in his threesome.
Fred Couples was 9-under-par for the day entering the final two holes at Las Colinas. Needing a birdie-birdie finish to shoot 59, Couples, winless since 1998, instead went bogey-bogey.
It was a bitter finish to what would have been a sweet round. After his 63 ' easily his low round of the season ' Couples waltzed past reporters, denying interviews.
News, Notes and Numbers
*83 players made the cut, which fell at 1-under-par 139. Among those missing the cut was Charles Howell. Roughly $10,000 away from earning an unlimited amount of sponsors exemptions (by rule, he has seven in 2001), Howell shot 73-68 for a 1-over-par total of 141. In five starts this season, Howell has two top-7 finishes and three missed cuts.
*Thursday, 20 of the top 21 players on the leaderboard played Cottonwood Valley. Friday, 15 of the top 21 played Las Colinas. The final two rounds will be played exclusively at Las Colinas.
*Robert Damron said he has switched his driver, his ball and his putter in the last three weeks. Hopefully, I have the right combination this week, he joked.
*Kenny Perry said he used a cross-handed putting grip in the first round and on each of his first two holes in the second round before switching back to the more comfortable conventional style. It must have worked. Perry shot 65 to move to 7-under for the tournament, four strokes off the lead.
*David Duval and Scott Verplank, the final pairing on Saturday, will tee off at 12:35pm local time.
Full-field scores from the Verizon Byron Nelson Classic