COMMERCE CITY, Colorado -- If the United States women's national team's 4-0 win over South Korea on Saturday at Dick's Sporting Goods Park was any indication, the stagnant attack from last year's World Cup is fully an issue of the past.

The era of Emma Hayes as USWNT coach got off to a slow first half-hour before forward Sophia Smith turned quickly and slotted a ball to winger Mallory Swanson for the first goal of the match in the 34th minute. Swanson made a slashing run behind South Korea's back five and tucked the ball away for her first of two goals on the night in a play that exemplified both the team's patience and the front line's fluidity.

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"I think something that's really good about Emma's style and the way that she wants us to be fluid in our structured principles, so I think she gives us a lot of freedom," USWNT midfielder Catarina Macario said after the match.

Macario played the No. 10 role on Saturday in her first start for the national team in 781 days. She pressed into high areas alongside Smith, the USWNT's No. 9, as the USWNT built attacks with five players across the front line at times. Macario also frequently flared out to wide areas to find the game. Swanson would shift inside at times, too, and she moved into the No. 9 role late in the match after a series of substitutions. Trinity Rodman rounded out the front four for the USWNT with her usual persistent effort on both sides of the ball on the right wing. The interchange between those four players specifically is a welcomed sign for a team that was too rigid -- a word Hayes used recently to describe what the team must avoid -- at the 2023 World Cup, where the USWNT's round of 16 exit marked the program's worst finish at a major tournament.

Swanson and Macario were both absent from that squad due to injury. Swanson was arguably one of the best players in the world before tearing her left patella tendon last spring, and former USWNT head coach Vlatko Andonovski was developing Macario as the focal point of the attack in 2022 before Macario tore her left ACL. Hayes now has the benefit of those two players healthy, not to mention the luxury of bringing Crystal Dunn, Rose Lavelle and Jaedyn Shaw off the bench in the second half to add fresh legs to the attack.

Shaw, 19, is the USWNT's leading scorer this year and one of the most versatile and creative attacking players in the pool. On Saturday, Shaw played primarily in a left-wing role alongside Swanson.

Hayes said on Friday that she divides her coaching responsibilities like American sports teams do, with different coaches specializing in different areas of the game. The attacking third is her responsibility, so Saturday's front line was a first look at how a USWNT pool loaded with scoring talent might operate with Hayes now on the sidelines, following a six-month waiting period while she finished the European season at Chelsea.

The new head coach praised her team's ability to process a lot of new information this week, but she stressed on Saturday that there is room to improve. The Americans were slow and, at times, disjointed in the first 30 minutes on Saturday. South Korea earned an early corner kick and got near goal only as a byproduct of the Americans' mistakes. The USWNT eventually settled into the match, and the opening goal came from a patient spell of possession that ended with center back Naomi Girma on the ball in an advanced position. She played Smith, who turned and quickly slotted Swanson for the goal.

"In terms what I had asked from the group, what we prepared for, the execution of that -- we've made steps in the right direction," Hayes said. "I felt for the first 30 minutes, it was technical execution where we struggled. We scored in our first three chances, so we were efficient, we were clinical."

She added that "there's another level" still to be reached by Smith, particularly in her combination play with Swanson.

The USWNT faces South Korea again on Tuesday in St. Paul, Minnesota, in the team's final match before Hayes must choose her 18-player Olympic roster. She is spoiled with attacking talent to choose from, and each decision she makes about how to set up the front line has a knock-on effect on the rest of the positions. Alex Morgan reaffirmed her role as the team's No. 9 earlier this year, but Morgan did not play on Saturday. Hayes called it a precaution due to pelvic tightness in training on Friday, noting that the staff wanted to play a "nice and fresh" Morgan on Tuesday.

Smith has long been the other natural option in that striker role, but last year she was shoehorned into a wide role next to Morgan and the entire front line struggled at the World Cup. Smith's central presence on Saturday underscored why that is her best role.

Rodman remains ever reliable, having played in every USWNT match since the start of 2023. She was active throughout Saturday's match, sparking passing sequences after regaining the ball in deep areas and getting to the end line to serve crosses.

Macario is the maverick within the group. She is a generational player who can thrive as a No. 10 with freedom, or she can pull out defenses as a striker.

"I have hindsight because I've coached her at club level, so I know how she operates in pockets," Hayes said. "She can draw players in, she can escape pressure -- she's a quite press-resistant player, links really well."

Hayes said that she "really enjoyed the front four in the first half."

"Fluidity" is a common way to describe Hayes' tactics, and that was on display in attack on Saturday. Hayes, however, has also consistently tempered expectations, stressing the need for processes. She's pragmatic -- and she isn't nearly satisfied yet.

"I think you can see we're building something," Hayes said. "There's lots of work to do. There's lots of holes in our play, no question, but it was a good start."