Behind him the scratch riders Phil Groves, Jason Sturzaker, Adrian Pettit and Bevan Cheatley caught the break bunch consisting of Brian Scrimshaw, Darcy Forrester, Steve Cowan, Allan Luff and Paul Forrest on the same climb on the last lap.
Scrimshaw attacked hard at that point and briefly went clear, but was reeled back in before the turn onto Rapanui Rd.
Meanwhile, up front Black had knuckled down to his work and made the turn into the Francis Rd finishing straight with a small margin over Chambers, which he maintained to the line. It was another well-earned win for Black who puts in plenty of mileage to ensure he stays competitive against much younger rivals.
Chambers clung on desperately for second place, doing very well to finish just metres ahead of the flying Jason Sturzaker, who out-sprinted the main bunch to claim third and take the days' time honours in 1h12m31s.
Cowan was right in the firing line in fourth spot, just ahead of Forrester in fifth, with workhorse Pettit rounding out the top six.
In the four-lap B-grade race, Carl Rusden won the bunch sprint to take the major prize money producing a good burst to win from the consistent Murray McDonald, with Craig Bright a handy third.
The C-graders raced over two laps over 18km and it was Stacey Hildreth, returning to the fray after a winter break, who cleared out with Graham Hall and then outsprinted him to take the win.
After a gap, Joseph Loveridge-Mills burnt off Dean Blackwell in the race for third place, with Mark Stoneman coming home fifth.