"I made a lot of birdies and when I was six under after nine it started to get serious - it wasn't so much fun any more.''
He described the two-round qualifying system with three Open places available for a 70-man field as one which can produce a "hit and miss'' approach.
"I wouldn't say you don't care but you certainly don't try as much.
"Perhaps that's the key to playing good golf sometimes.''
Brown lost his European player's card in 2011 after four years and last year played mainly the OneAsia and Australasian tours.
He finished third at the Australian Masters at Kingston Heath last November and said the course "probably suits me''.
Brown had a breakout year in 2008, when he won his first Asian Tour event at the SAIL Open Golf Championship in India and the following week took out the Johnnie Walker Classic.
That lifted him to 64th in the world golf rankings and he finished the year by winning the PGA Tour of Australasia's Order of Merit.
Brown's birdie barrage began at the second and by the time he had reached the turn, courtesy of three further birdies and an eagle three at the seventh he was six under par.
The flawless form continued on the homeward nine as Brown collected four more shots.
He has played the British Open once before, in 2009 at Turnberry, missing the cut, although he finished 24th in the US PGA Championship the previous year.
-AAP
