Overnight leader Padraig Harrington continued his good form as he began his second round at the World Golf Championships-Bridgestone Invitational in Ohio.
Three-time Major winner Harrington produced his best round of the year when he posted a six under par 64 at Firestone Country Club to take a two shot opening round lead over Thailand's Prayad Marksaeng, Tim Clark of South Africa and American Scott Verplank.
The Irishman picked up where he left off, moving to seven under after five holes having birdied the par five second when he shot out of right rough from 71 yards to six feet from the hole.
Playing partner Verplank remained at four under after five holes, with Marksaeng and Clark drawn to start in the later wave of players in the 80 man field.
Former Masters Tournament champion Zach Johnson made sure reigning US PGA Championship winner Harrington's lead was kept at two shots as he birdied his first two holes having started from the tenth hole and was at five under par after four.
Harrington's other playing partner, Søren Hansen of Denmark, also started brightly with birdies at the first and fifth holes to move to three under, a mark American Woody Austin had also reached after eight holes.
World Number One Tiger Woods was another early starter and parred five holes to remain at two under, with playing partner Sergio Garcia of Spain on the same mark having birdied his opener, the par four tenth.
England's Oliver Wilson joined them at two under after six holes thanks to a birdie at the par four 11th but compatriot Ian Poulter undid his strong start to the tournament.
Poulter had begun the second round at three under but, starting on the back nine, he bogeyed the 14th and 15th to fall to one under after six holes.