O'Reilly, who finished with a goal and an assist on eight shots, was named Player of the Game for Canada. He skated 21:21, far and away Canada's leader among forwards, a feat made more impressive when you consider he's playing on a team with names such as Claude Giroux, Wayne Simmonds, Nathan MacKinnon and Mark Scheifele.
Only one defenseman - Colton Parayko, at 22:57 - skated more than O'Reilly.
The effort would have been for naught had it not been for a third-period comeback that saw the Canadians erase a two-goal deficit. They came out of the second intermission with 30 seconds remaining on a man advantage, and it only took 17 for Scheifele to finally beat Russian goalie Andrei Vasilevskiy and cut the deficit in half.
The Canadians earned three more power plays in a third period that saw them outshoot the Russians 19-5, but it wasn't until MacKinnon's even-strength goal with 4:53 remaining that they finally evened the score, setting the stage for O'Reilly's grand finale.
O'Reilly has scored five goals and three assists in nine games, matching the eight points he scored en route to a gold medal with Canada a year ago. Those numbers, combined with his two-way presence, earned him recognition as one of Canada's top three players at the tournament along with Scheifele and Mitch Marner.
Canada will play the winner of Saturday's semifinal between Sweden and Finland in the gold medal game at 2:45 p.m. on Sunday. A win in that game will give O'Reilly his third gold medal at the event.
For O'Reilly, you can bet that's the only number that matters.