Chalk it up to parity. Or great defending.
Or maybe, as Abby Wambach said, it's the artificial turf.
Whatever the reason, goals have been hard to come by at this women's World Cup.
Twenty-four of the tournament's 44 games — including five of eight in the round of 16 — have ended in shutouts. In group play there were two games in which neither team scored — the first time there have been two scoreless draws in the World Cup since 1999.
And that's a trend that favors the U.S., which has given up only one goal in four games and will enter Friday's quarterfinal with China working on a streak of 333 scoreless minutes.