* McIlroy fires a bogey-free 68 to take control * Scott and Johnson share second place * Spieth a distant 10 shots off the pace (Adds quotes, detail) March 5 (Reuters) - Rory McIlroy again benefited from his new putting grip as he overhauled halfway leader Adam Scott to move three strokes clear after the third round of the WGC-Cadillac Championship in Miami on Saturday. Two shots behind Scott overnight, the Northern Irish world number three racked up four birdies in a flawless display to card a four-under-par 68 on the difficult Blue Monster course at Trump National Doral Resort. McIlroy, seeking his first victory since the European Tour's season-ending DP World Tour Championship in late November, parred the last three holes on the brutal closing stretch to post a 12-under total of 204. More...