By Miles Evans
ST ANDREWS, Scotland (Reuters) - Louis Oosthuizen set about reeling in Rory McIlroy's overnight British Open lead with real gusto in the hammering rain at St Andrews on Friday, moving one clear of the field after a superb outward 33.
The 27-year-old South African quietened the doubters who thought the man who had never made an Open cut in three tries would slip back after an opening 65 by ramming in three birdies in a row from the fifth and another at the 10th to go 11 under.
McIlroy, the 21-year-old Northern Irishman who illuminated a grey Old Course on Thursday with a record 63, tees off at 1231GMT.
Among the other early movers on Friday when heavy cloudbursts came and went was 1989 champion Mark Calcavecchia.
The 50-year-old American, who struck the first tee-shot on the second day of the 150th anniversary tournament, carded four birdies through 13 holes to go to six under, one behind Barnes who eagled the par-five fifth.
England's Paul Casey opened with three consecutive birdies to join the group on six under.
World number one Tiger Woods, right in the mix after an opening 67, tees off at 1320.
(Editing by Tony Jimenez)
