FORT WORTH, May 24, 2014 (AFP) - The 22-year-old Asian star joined Americans David Toms, Chris Stroud and Chad Campbell on seven-under 203 after 54 holes.
Six others were only one stroke off the pace while another seven players were two strokes adrift, setting up a final-round Sunday shootout.
"I'm going to probably be nervous tomorrow," Matsuyama said. "I'm going to have to shoot lower tomorrow. I'm going to do my best."
Matsuyama won four times on the Japan Tour last year and has two top-five efforts in his first US PGA season, a share of third at the Frys.com Open last year and a share of fourth in February at Phoenix.
In his past five starts, Matsuyama has struggled, missing two cuts, twice finishing outside the top 30 and withdrawing from the Honda Classic with a wrist injury.
"Gradually, week by week my game has gotten better," Matsuyama said. "I feel like I can compete now -- especially to shoot six-under and be in contention."
Matsuyama sank a 12-foot birdie putt at the second hole, added another from 15 feet at the par-3 fourth and dropped a 25-foot birdie putt at the fifth.
After a five-foot birdie putt at the par-5 11th, Matsuyama sank a 13-foot birdie putt at 14 and put his drive at the par-3 16th just five feet from the cup to set up his final birdie.
Stroud birdied the final hole to shoot 69 and join the lead pack while Campbell shot 68 while Toms, the 2001 PGA Championship winner, fired a 65.
Toms likes Colonial because as a formidable yet short course it provides a stern test for a variety of players.
"It evens all of us out, long hitters and short hitters. You bite off what you can chew out there," Toms said.
Sitting on 204 were Australian Marc Leishman, South African Tim Clark and Americans Kevin Chappell, Chris Kirk, Jimmy Walker and Brian Harman.
Chappell fired a 63 after starting with six birdies and an eagle in the first 11 holes, including four birdies in a row to finish the front nine, but he closed with a bogey at 14 and six pars.
"I used up a lot of luck," Chappell said. "I had two chip-ins and made some long putts."
- Scott in fight for No. 1 -
Adam Scott, playing this week for the first time as world number one, shot a bogey-free 66 to join a group on 205 that included fellow Aussie John Senden, England's Brian Davis, Sweden's Freddie Jacobson and Americans Jason Dufner, Bo Van Pelt and Brendon Todd.
Scott birdied three of the first four holes and closed with 10 pars in a row to claim a share of 11th.
"I'm feeling good," Scott said. "I was executing how I wanted to come out. Everything went according to plan on the front. Unfortunately I couldn't keep my momentum going."
Scott, who supplanted injury-idled Tiger Woods atop the world rankings on Monday, could be overtaken this week by Sweden's Henrik Stenson, who shared seventh entering the final round of the European PGA Championship at Wentworth.
"I can only worry about my golf here," Scott said of Stenson possibly overtaking him. "Worrying about that isn't going to help me at all.
"It's all very tight. We know that. I'm happy to have gotten to number one. I hope it's not such a short stay."
While the 2013 Masters champion put himself into contention for the title in Sunday's final round, Scott admits the challenge to win will be difficult because so many rivals are ahead of him.
"It's going to be tough," Scott said. "There's a lot of people between me and the lead."
Leading scores after Saturday's second round of the $6.4 million USPGA Tour's Colonial tournament (USA unless noted, par-70):
203 - Hideki Matsuyama (JPN) 69-70-64, David Toms 72-66-65, Chad Campbell 69-66-68, Chris Stroud 70-64-69
204 - Kevin Chappell 68-73-63, Chris Kirk 73-64-67, Marc Leishman (AUS) 69-68-67, Brian Harman 69-67-68, Tim Clark (RSA) 67-68-69, Jimmy Walker 67-68-69
205 - Adam Scott (AUS) 71-68-66, John Senden (AUS) 71-68-66, Brendon Todd 69-69-67, Freddie Jacobson (SWE) 67-17-67, Jason Dufner 67-69-69, Brian Davis (ENG) 68-67-70, Bo Van Pelt 67-68-70
206 - William McGirt 72-67-67, Robert Allenby (AUS) 68-70-68, Ryan Palmer 69-69-68, Nicholas Thompson 69-68-69, Tim Wilkinson (NZL) 66-71-69, Jordan Spieth 67-69-70, Aaron Baddeley (AUS) 68-67-71