Teen prodigy Jordan Spieth, trying to become the youngest US PGA Tour winner in 82 years, fired a five-under par 66 Friday to share the lead in the second round of the storm-halted National.
The 19-year-old American, a former world amateur number one who turned professional last December, matched countryman Roberto Castro for the lead, both at seven-under 135 through 36 holes at Congressional Country Club.
"Felt like a really solid round," Spieth said. "I'm excited for what the weekend is going to bring."
Spieth, who turns 20 on July 27, would become the fourth-youngest winner on the all-time US tour list and the youngest US tour champion since 1931, with Ralph Guldahl three months younger when he won that year's Santa Monica Open.
"It would be huge," Spieth said. "I can't really think about that at this point. It's only halfway through so there's a long way to go."
There were 64 players yet to finish the second round when a series of afternoon thunderstorms ended play for the day, the top contender among them being Argentina's Andres Romero at five-under overall with five holes to play.
The second round will resume Saturday morning with plans to complete the third round Saturday afternoon.
South Korean rookie Lee Dong-Hwan, last year's PGA Qualifying Tournament winner who is fighting to keep his tour spot at 129th on the money list with $364,830, also charged into the hunt, firing a 66 to stand third on 137.
"To be playing this well on a course all the players say is tough, I'm just very happy. I couldn't ask for more," Lee said. "My goal is to retain my card and I'm fairly confident that I'll be able to gain my card back for next year."
Spieth has earned special temporary tour membership for the remainder of the season after winning $919,079, all but clinching a 2014 tour berth. Four top-10 efforts in 13 starts this year include a runner-up finish at Puerto Rico.
A victory would bring instant PGA membership, including a berth in this year's playoffs, and a tour spot for two years.
"It has been a great dream come true this year," Spieth said. "I'm just free swinging. I can't be in the playoffs unless I win and that makes winning the number one goal... I don't have to worry about making x number of dollars."
Spieth sank a 25-foot birdie putt on the first and birdied four of the last five holes on the front side, including back-to-back birdies at the par-4 fifth and par-5 sixth and par-4 eighth and par-5 ninth, then parred the back nine.
"You don't try and stall like I did on the back nine, but I was trying to push for a couple more birdies and almost had them," Spieth said.
"I felt the nerves, just like anybody does trying to win for the first time when you see yourself in the lead."
First-round leader Castro took a bogey at the par-4 third after finding a bunker off the tee but answered with birdies at the eighth and ninth plus another at 16 to finish on 69.
"A lot of confidence going into the weekend," Castro said. "I feel good about two rounds in the 60s. That means you've gotten the ball up and down and you're going to have to keep doing that."
Lee began on the back nine and birdied the 12th, 15th and 16th holes before a bogey at 18. He birdied the first and third and after a bogey at the fifth made birdies at the sixth and ninth, closing with a nine-foot birdie putt.
"The rough is so long, if you're not on the fairway, you're going to have a hard time getting on the green," Lee said. "My good drives definitely helped my rhythm and contributed to the score."
Lee, a two-time winner on the Japan Tour, shared eighth at New Orleans in April for his best result in 17 career PGA starts.
"I had big expectations, but I really didn't know what to expect," Lee said. "As time went by, I started learning, adjusting. My short game, my putting, it has gotten better."