Cheltenham appeared to be cruising to victory when they led 8-4 midway through the third period.
But the next five goals came in quick succession from Winstanley (2), Joe O'Regan (2) and Rob Rae, putting Manchester ahead for the first time at 9-8. The lead increased to 11-9 before Michael Thomas replied for Cheltenham a minute from the end.
Caledonia fought back from 7-3 down to draw 11-11 with Sheffield. Logan Shepherd scored a final equaliser for the Scots 22 seconds from the end.
Lancaster were too good for Team Northumbria, winning 13-8, including five goals by Tom Curwen.