US Open champion McIlroy carded an eventful two-under-par 69 to join fellow Britons Simon Dyson (68), Gary Boyd (69) and Jamie Donaldson (66) on eight-under 134.
Last year's U.S. PGA champion Martin Kaymer (70) was in a group of five players one stroke off the pace. Also on 135 was overnight leader Nick Dougherty, the Englishman having returned a 72 to make his first cut of a woeful year.
World No.?2 Lee Westwood was a further shot adrift on 136 after a 69. Most of the field suffered on ragged Crans-sur-Sierre greens and McIlroy was no exception, though it was the fifth and ninth holes that influenced his round most. On the fifth the Northern Irishman slammed a stunning drive to just three feet and sank his putt for an eagle two. Then he undid his good work by three-putting from six feet on the ninth for a double-bogey seven.
