When the American Outlaws broke out into their signature “I believe” chant in the 58th minute during yesterday’s game against Nigeria, Sydney Leroux and Christen Press could easily have joined from the sideline. After starting the first two games, Leroux and Press, two of the best attacking players in the world, were dropped in favor of Alex Morgan — who, remarkably, was starting her first Women’s World Cup game ever — and Abby Wambach, who scored the game’s first and only goal just before halftime.

A few minutes later, American head coach Jill Ellis called Leroux’s no. 2 and sent her into the game. The speedy forward attacked a weary Super Falcons back line and quickly drew a foul on overmatched 19-year-old defender Sarah Nnodim, who picked up a second yellow card and was sent off. While the Americans failed to find a second goal with the numerical advantage, Leroux’s injection of pace in the final third of the match showed what makes the squad so dangerous in the attack: They have the potential to punch you in the mouth at the beginning of the game, wear you down with body blow after body blow, and then bring in another world-class attacker to finish the job.

In a tournament played on unforgiving turf and with games basically every four days — the U.S. doesn’t play again until the 22nd, courtesy of their first-place finish in Group D — most teams won’t have the ability to rest and recover. For the U.S., who’ve played three different forward pairings in three games, the ability to shuffle pieces while not losing anything in the attack could prove to be invaluable. At least, that’s the hope.

Options off the bench would appear to be a reward Ellis gets for coaching one of the deepest teams in the tournament, but they also can potentially restrict flexibility. After her goal yesterday, it seems even clearer now that Wambach, who played all 90 minutes, has to start. Still, she looked tired at the end of the match against Nigeria. It didn’t matter — especially once the Americans went up a player — but as the competition gets tougher further into the tournament, the team can’t afford to be carrying a player running on fumes. If Morgan starts, too, she also might not last 90 minutes, as yesterday was her first start since early April. That’s two of Ellis’s three subs right there. Going into a game knowing you have to sub both of your two forwards limits tactical options, and it cuts down your margin for error, especially if anyone other than Wambach or Morgan gets hurt. Of course, you can slide Wambach or Morgan to the bench in favor of another player who can go the full 90 (or 120), but then you’re not playing one of the team’s two most recognizable faces, which brings about its own problems.

Over the next few weeks, Ellis will have to turn this depth into a weapon. Since that magical summer of 1999, shuffling playing time, keeping everyone happy, and winning games has proven to be a nearly impossible task for whoever’s been managing the USWNT. Of the two previous coaches, Pia Sundhage was never flexible enough, while Tom Sermanni’s flexibility led to a player revolt. Ellis, U.S. Soccer’s former director of player development, knows the strengths and weaknesses of her pool better than the previous two managers did. She has never coached at this level before and the U.S. didn’t necessarily breeze through its group, but she has shown a promising willingness to rotate her squad through the first three games. More importantly, the team enters the knockout round looking relatively fresh and without any injuries. The further the Americans get into the tournament, the better they will be for having spread out minutes, especially since Morgan and Wambach are running themselves back into full fitness while playing some of the most intense soccer matches of their lives.

The knockout stage begins early next week against, well, someone, followed by a quarterfinal against China or Cameroon and a likely semifinal battle with Germany lurking. With seven points and a first-place finish, the U.S. survived the Group of Extreme Exhaustion. Now the real heavy lifting begins. Even though it’s tiny, you can’t pick up the World Cup trophy unless everyone pitches in.

Noah Davis (@noahedavis) is Grantland’s United States men’s national team columnist and deputy editor at American Soccer Now.