Mount Wellington finished the match with ten men after Dave Witteveen was sent off late in the second half.
Allan Carville led the way for the southerners, before a wayward backpass from Verweij caught the wind and beat his own keeper to level things up.
The Mount took the lead for the first time with a fine curving shot from Noel Barkley, 1990 New Zealand player of the year.
Then in the dying stages, referee Roger Woolmer game a free kick to Mount Wellington close to the Christchurch goal.
Christchurch fought back, and with only seconds remaining McGarry deflected a Julyan Falloon cross into the Mount's net.
Mount Wellington scored with four of their five efforts, from Terry Torrens, Noel Barkley, Grant Lightbown, and Steve O'Donoghue.