Rory McIlroy started to make his move at Royal Troon with three birdies in the first seven holes to climb into a tie for fifth place at The Open.
The 2014 champion got to within five shots of leader Phil Mickelson, though he had to scramble par from a green-side bunker at the Postage Stamp eighth to maintain his bogey-free second-round scorecard.
While the Northern Irishman sat on five under, another pre-tournament favourite was starting to see his hopes fade.
Jordan Spieth could only make par in favourable conditions on Thursday and found himself the wrong side of the projected cut line after going three over through 10.
Mickelson's three-stroke overnight lead was shortened to one by Henrik Stenson's 65 earlier on Friday.
If McIlroy is to make further headway, he must avoid a repeat of his back-nine troubles from Thursday, when he dropped three shots over the 13th and 14th holes.