from Jeff Gordon of the St. Louis Post-Dispatch,

...the NHL being the NHL, it opted to give coaches the right to challenge goals by demanding video of review of such borderline passes at the blue line. The rule brings games to a screeching halt and takes goals off the board for violations that are far from obvious.

And one such video challenge tore the heart out of the Blues Friday night at Scottrade Center and imperiled their postseason hopes.

Vladimir Tarasenko lost his go-ahead goal late in the third period to Blackhawks coach Joel Quenneville's challenge. Then, perhaps out of frustration, he took a slashing penalty.

Naturally the Blackhawks converted that power play (and a subsequent empty-net opportunity) into a 3-2 victory.

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Below, watch the Quenneville challengs and a part of Ken Hitchcock's post-game press conference, plus the Andrew Shaw goal...