Seamus Power remains on eight under ahead of the final round at the Travelers Championship but Rory McIlroy slipped down the leaderboard on day three.
Both started Saturday on eight under but while Power carded a level-par 70 to finish the day nine shots off Xander Schauffele's lead, a two-over round proved costly for McIlroy, who slipped into a tie for 31st at the TPC River Highlands course in Connecticut.
Schauffele holds a one-shot lead over Patrick Cantlay on 17 under after his 67 followed up two opening rounds of 63.
Cantlay put himself in contention with his own 63 to sit second, two clear of Sahith Theegala who carded a 64 to move up to 14 under.
Power's round got off to a decent start with a birdie on the second but the back nine proved more challenging with a bogey on 12 and double bogey on 15 sandwiching consecutive birdies on 13 and 14.
McIlroy, who teed off 10 minutes before the Waterford native, had a contrasting start, double bogeying the second and dropping another shot on the fifth.
Birdies on six, nine and 13 saw the four-time major winner rally effectively but he finished with bogeys on 14 and 16 to cancel out that progress.