The 24-year-old from Maidenhead matched O'Malley's seven birdies, but bogeys at the fourth and eighth, both par threes, dropped him into a share of third place, the Swede Max Anglert moving into second with a 66.
Jose Maria Olazabal, who described the bookmakers who made him favourite for the title as "a little bit insane", was not changing that view despite a two-under 70 in only his second event back after an 18-month injury lay-off.
Olazabal has now scored under par in four of his first five rounds back and yesterday received the Johnnie Walker golfer of the month award for February for his 12th-place finish in Dubai.
Seve Ballesteros is involved in a fight to avoid his fourth successive missed cut this season following a 73, while Howard Clark had a 74 which included a quintuple-bogey eight on the 142-yard 14th where he put three balls into the lake guarding the green.
Steve Richardson, second to Ballesteros on the 1991 Order of Merit, is facing a fifth missed cut in a row after a 78 and Sam Torrance slumped to an 81 without a single birdie.