Former champion Lleyton Hewitt lost to Germany's Brown in four sets in the second round of Wimbledon.
Brown, a qualifier ranked 189 in the world, prevailed 6-4 6-4 6-7 (3/7) 6-2 to reach the third round of a Grand Slam for the first time.
Hewitt, 32, has been plagued by injuries in recent years but his performances in reaching the semi-final at Queen's Club last week gave the Australian cause for optimism.
That was added to further when he shocked 11th seed Stanislas Wawrinka in the first round.
However, 2001 champion Hewitt was unable to seize any kind of control of the match, going down 6-4 in the opening set.