Game 4 of the final match at the 2012 Women's World Chess Championship was a must-win for Antoaneta Stefanova, and win she did. Trailing Anna Ushenina 2-1 after a loss in game 3, she at least had the advantage of the white pieces, and she used them successfully. She had a better sense than her opponent of how to play the Anti-Meran system in the Semi-Slav, and soon after leaving theory she had earned a completely winning position. Very near the finish line, she squandered most of her advantage with a series of second-best moves, but Ushenina missed her one chance to get back in the game and walked into a mating combination. (You can replay the game here.)
On to tiebreaks on Saturday!