Ireland's Padraig Harrington still had his nose out in front with nine holes to play at the PGA Grand Slam in Bermuda - but only just.
Leader by two overnight following an opening five under par 66, Harrington added birdies at the fifth and eighth, but US Open champion Webb Simpson matched those and also made gains on the third and long seventh.
Out in 32 as a result, Simpson was one behind, while Masters champion Bubba Watson and holder Keegan Bradley, both of whom covered the front nine in 34 like Harrington, were two back and six adrift respectively.
There is a £375,000 first prize on offer at an event meant to be between the year's four major winners, but Bradley replaced Rory McIlroy - he is playing in Shanghai - and last Saturday Harrington was called in as replacement when Open champion Ernie Els withdrew with an ankle injury.
