Dinnia Díaz was playing a game within the game, a mind trick familiar to anyone who has worked a shift at a job that isn't all that fun. When it was slow, she'd steal a glance at the clock, then try, try, try to let more time pass before she looked again.

A longtime goalkeeper for the Costa Rica national team, Díaz rarely feared opposing attackers or tried to count the minutes until the final whistle blew. It was different when she was facing Alex Morgan.

"Sometimes you're thinking, 'How much time is left? Can Alex still score on me?'" Díaz said.

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Once, in a 2016 friendly match, Díaz did manage to keep Morgan scoreless, though she did concede a goal assisted by Morgan. Another time, in Olympic qualification in 2016, Morgan scored nearly from kickoff and found a second goal in the 62nd minute.

"It was really meaningful because you want that such an extraordinary player with such a great career doesn't score on you. As a goalkeeper, that means a lot," Díaz said.

Playing international soccer is a joy, and the Women's World Cup (which kicked off Thursday) promises to be a monthlong expression of that positivity. But doing it against Alex Morgan can turn any day into a very rough day at the office.

Morgan and U.S. fans hope a new group of players have their days ruined at the Women's World Cup, which the Americans open Friday night (U.S. time) against Vietnam in Auckland, New Zealand. But a number of players in Concacaf and beyond are well-acquainted with that wait, the quick glances at the clock and the sense of dread that sooner or later, she's going to find a way to score.

Alex Morgan heads into this World Cup with 121 goals in 207 International appearances, putting her above an average of one goal every other game. She also has chipped in 49 assists. The résumé is well-known: a pair of World Cup winners' medals, a gold medalist and someone essentially impossible to stop.

Not that teams don't still have to try. In the opening match of the Concacaf W Championship last summer, the Haiti national team wondered if it might get a reprieve and see Morgan rested ahead of more daunting games later in the tournament. Instead, she started and scored twice in the opening 23 minutes as the U.S. wrapped up a 3-0 win.

"OK, we really have to turn it on right now," Haiti center-back Claire Constant remembers saying to her teammates after seeing Morgan would start. "There was no specific 'Defending Alex Morgan' training we were doing, but we were obviously aware of her talents."

While other players might take small breaks during the game, Constant says Morgan "never turns off."

"You have to keep an eye on her for literally all 90 minutes. Her movement off the ball, whether she's checking into the seams or making runs into the box, is very, very hard to defend," Constant said. "She's always making quick little movements and makes selfless runs for her teammates."

Diaz said that reflects itself in Morgan's positioning. She could be in the right spot for a tap-in, or she might shake off her defender to get alone at the top of the box. Since you never know, you're always counting those minutes.

"She adapts to any style of play and always makes things tough for opponents. She can pop up in different areas of the field, always is well-located, and makes goalkeepers and the whole defensive line think," Díaz said.

Bianca Henninger had to chuckle when she saw ESPN's request to speak with her for this story. "I mean, sure. Do you want me to talk about how she annihilated every team I was ever on?" she quipped.

Now in the Angel City FC front office, Henninger was a long-time NWSL shot-stopper who also suited up for Bayern Munich and the Melbourne Victory. A California native, she represented the Mexico national team and therefore had a number of showdowns with Morgan on the international level.

There was the Women's World Cup qualifier in 2018 in which Morgan scored twice in the second half, putting the bow on a 6-0 victory Mexico thought it could win at halftime, trailing by just one. There was the penalty in Jacksonville in a friendly, when Henninger said, "I knew where she was going to shoot. I guessed the right way, and it was fingertips away. That's the level of execution she brings to the table."

Even times when Henninger had the upper hand, she said the best-drawn game plans would come undone. "Good players like her find ways around the game plan," she said. "And, if they don't, they're pulling a ton of resources away from the stuff you're trying to do in regular soccer games."

Constant agrees. The U.S.-born defender and Virginia product grew up watching Morgan and only watched her more carefully when she saw the draw for the Concacaf W Championship, realizing she'd be tasked with shutting her down. The results of the study in the video room left her little to work with.

"It's very hard to defend someone with that much determination. When I'm going up against someone, I'll watch film and then on the field I'll look for what their weak spots are," said the Haiti defender, who will miss the World Cup because of an ACL injury suffered just before the tournament. "For me, Alex doesn't have any weak spots or she does a very good job of hiding them.

"You're never comfortable on the field when she's on the field with her."

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Players from the Concacaf region are sending a warning to Morgan's World Cup opponents: One moment of letting your concentration slip, one time a defender isn't able to execute the game plan, and it may mean picking the ball out of your net and shaking your head. Alex Morgan scores. Again.

"You always prepare not to concede but doing it against a player with that style of play that's so natural and where she can change a game from anywhere. You've got to pay attention," Díaz said.

The games might only last 90 minutes, but when you keep stealing peeks at the clock while trying to find Morgan around the box, it can feel much longer.