The 29-year-old scored a bullet from the blueline on a five-on-three powerplay as GB came from behind to secure their second victory in three games.
"That was a special way to crown my 50th cap to get the game-winning goal and the man-of-the-match award," said O'Connor.
"I am so proud to pull on the GB jersey and to do it with your best friends is very special indeed."
O'Connor is second on the points-scoring list for GB defencemen with 15 goals and 25 assists, only behind Jonathan Weaver.
GB were 3-2 down at the end of the second period but two goals in two minutes turned the game around and another Steeler, Jonathan Phillips, wrapped the game up, scoring into an empty net.
"We had to dig deep and find a way, so this was a gutsy performance," continued O'Connor.
"Words were said in the dressing room at the second interval as we know we weren't good enough.
"But we battled to the end and I think we deservedly came out on top."