With two and a half minutes remaining, it was still 13-11 to the Marlins. But Grace's two goals in the space of 15 seconds brought her side level - and Tyldesley held on as their opponents failed to cash in on Tyldesley exclusions near the end.
Otter Lutra, who beat Caledonia and Mid Sussex Marlins - both by 7-4 - and Leeds Sharks were the only teams to win their two matches. Leeds defeated West London Penguin 8-7 and Liverpool Liver Birds 7-3.
Caledonia celebrated St Andrew's Day in style by trouncing fellow Celts Welsh Wanderers 12-1.