One aspect of the beautiful game that goes largely unnoticed is one of the single most important parts of the sport: the mental side. During the FIFA Women's World Cup France 2019™, the USA squad have already been put through some stern examinations both physical and mental - arguably the toughest of which so far came against Spain in the last 16.

Whether it is fitness, technical, or tactical play, the psychological piece of the puzzle can test a team’s true colors. With a sports psychologist on hand, the US team has made a point to making the mental part of the game just as important as the physical.

Every single player on the USA squad discusses how important it is to be in the moment and to not focus on the future or the past and to only control what they can control.

Christen Press and Rose Lavelle have both discussed how meditation has become a part of their routine and what it has done for them as players.

“This is something I’ve taken very seriously the past year," Lavelle said. "Because as much as you want to feel good physically I think the biggest battle is how you feel mentally stepping on the field. I think a lot of us mediate and visualize.”

Press told FIFA.com that before each match she likes to visualize herself as an African big cat ready to pounce.

Each player has something different to mentally prepare them for what they are about to do, but there are not many U.S. players who will have foreseen the circumstances of how the game played out against Spain. La Roja came out playing a fast and physical style of play, forcing the U.S. out of their regular rhythm.

Tobin Heath was tripped up in the box during the first six minutes, with Megan Rapinoe giving the Americans the early lead they have taken in every match so far this tournament.

After scoring 18 goals and allowing none in group play, the U.S. seemed shell-shocked when a miscommunication led to the first conceded goal of the tournament for the Stars and Stripes minutes later. How they would bounce back from that was a true testament to the identity and mental toughness of this team.

“Tonight, I thought that mental piece - you can have all of the tactics in the world,” coach Jill Ellis said. “But that essence of self-belief, that’s critical and these players have that.”

It was 1-1 nearly the entire match while both teams battled it out. But the U.S. never let the physicality and pressure get to them. Another Rapinoe penalty would give USA the 2-1 win over Spain to move onto a quarter-final against host France. With a no doubt boisterous Parisian crowd waiting on Friday, Jill Ellis's side will need to dip into those reserves of mental toughness once again.

Fans interested in attending the FIFA Women’s World Cup 2019 can still purchase tickets for the tournament via www.fifa.com/tickets, as well as via ticket booths located at stadia for remaining matches still available to the general public.