Tiger Woods remains on course for his eighth Bridgestone Invitational title after preserving a seven-shot lead with one round to play.
The American followed up Friday's career-equalling best 61 with a 68 to leave him on 15 under par in Ohio.
Sweden's Henrik Stenson moved into second on eight under with American Jason Dufner a shot back in third.
England's Chris Wood and Luke Donald are in a three-way tie for fourth on six under.
But there appears to be no stopping Woods, who, chasing his fifth title of the season, started his third round with consecutive birdies.
After six straight pars the 37-year-old closed the front nine with a bogey but responded with a birdie at the 10th.
Woods birdied the 13th but took a bogey at the next hole and continued the up-and-down run with a bogey at the par-five 16th followed by a birdie at the par-four 17th.
The best round of the day came from Spain's Miguel Angel Jimenez, who carded a 65 to move into tied seventh on five under.
Northern Ireland's Rory McIlroy showed improved form as he shot a one-under 69 but remained well off the pace.
His first sub-par round of the week left him on level par and in a share of 17th, alongside England's Ian Poulter and Justin Rose.