Mexico's final international break provides El Tri with five key lessons
Mexico's final international break before the pre-World Cup camp in May saw El Tri defeat Iceland 3-0 at Levi's Stadium in San Francisco and lose 1-0 to Croatia at Dallas' AT&T Stadium, with a total of just under 150,000 fans attending the two games.
The results were largely peripheral in terms of what coach Juan Carlos Osorio was looking to see from this squad as the countdown to Russia 2018 continues.
Here are five lessons we learned:
1. Eighteen of the 23-man World Cup squad is set
How many of Mexico's squad does Osorio already have in mind for Russia? It isn't too difficult to deduce after the past two games and the failures of some of the youngsters to step up.
It would be a major surprise if any of the following are not in Mexico's final 23-player World Cup squad: Guillermo Ochoa, Jesus Corona, Alfredo Talavera, Hector Moreno, Miguel Layun, Diego Reyes, Jesus Gallardo, Andres Guardado, Marco Fabian, Hector Herrera, Jonathan dos Santos, Javier Aquino, Javier Hernandez, Carlos Vela, Oribe Peralta, Raul Jimenez, Jesus "Tecatito" Corona and Hirving Lozano.
The cases of injured duo Nestor Araujo and Carlos Salcedo remain potentially delicate, but the fact that they are two of Osorio's most dependable defenders means the coach will give them every opportunity to recover and be part of the squad, even if they don't play much between now and then.
There is an ongoing debate/debacle surrounding Atlas' 39-year-old Rafa Marquez, whose legal situation remains complicated, though Osorio has hinted that he is keen to take the veteran to his fifth World Cup. Then there is Giovani dos Santos. You'd back Osorio to pick Dos Santos right now, but a little bit of form for LA Galaxy would do him no harm at all to ensure his place.
If you were then to second-guess one more player, it'd be another center-back, likely one of Hugo Ayala or Oswaldo Alanis.
Behind them are the likes of Rodolfo Pizarro, Jurgen Damm, Orbelin Pineda, Jonathan Gonzalez, Jorge "Burrito" Hernandez, Erick Gutierrez and Omar Govea.
2. Herrera injury a major concern
The injuries to Araujo and Salcedo might have garnered more headlines in the immediate aftermath of Mexico's loss to Croatia, but Herrera's injury is potentially just as concerning. Only Hector Moreno has played more national team games than Herrera (28 games) since Osorio took over in October 2015.
Herrera traveled back to Porto on Sunday with a recurring and unspecified injury that has the Mexican federation and Osorio concerned.
The midfielder underwent a scan while with the national team, and as soon as the results were seen, there was no chance that Herrera was going to see the field against Iceland or Croatia.
The issue now is that the Mexican federation is extremely worried that if Herrera continues to play with the injury for Porto -- who are currently in a tight battle with Benfica and Sporting for the Portuguese title -- it could cause an even more serious complaint. With the World Cup fast approaching, that wouldn't be at all good for El Tri.
Herrera is arguably Mexico's most important individual for Russia. He has created the most chances (46) and has more assists (7) than any other player in the Osorio era.
3. Jonathan Gonzalez a long shot, Marquez would be helpful
Bay Area native Gonzalez caused one of the biggest stirs of the year in Mexican football when it was confirmed that he would switch international allegiance from the United States to Mexico. The 18-year-old Monterrey midfielder made his debut in January's game against Bosnia and Herzegovina but wasn't involved in either game over this international break.
He was carrying an injury coming into camp, but the writing seems to be on the wall when it comes to the World Cup: He's on the outside looking in as of right now. It was always going to be difficult for Gonzalez to work his way into the 23, though the position from the Mexican federation has always been that the player has a bright future with El Tri. That hasn't changed.
At the other end of the spectrum, 39-year-old Marquez's continued absence was perhaps felt in terms of leadership, especially against Croatia. Osorio respects Marquez's opinion greatly, and in terms of providing that link between the coaching staff and the players, it's better to have the Atlas player around.
It also won't have gone unnoticed that Guardado and Ochoa both hinted after the Croatia loss that the time for experimentation is over, with the World Cup so close.
4. Holding midfield remains problematic
At the risk of sounding like a track on repeat, the holding midfield position is still open and proving difficult for Osorio to solve. The Colombian wants a player in the mold of Sergio Busquets -- what manager wouldn't? -- but doesn't have one in the Mexican player pool.
The dilemma is whether to go for Reyes -- in a similar way to how Carlo Ancelotti used Sergio Ramos for a time at Real Madrid (the less defensively minded Herrera makes up for that inferiority with far superior vision and range of passing) -- or whether to pick Jesus Molina, a natural holding midfielder who plays it simple out from the back.
The other option would be to change the structure of the midfield to include two predominantly holding mids.
The 3-4-3 diamond formation proves problematic
Contrary to popular opinion in Mexico, Osorio isn't throwing around formational changes at a whim. There are underlying reasons he started with a 3-4-3 diamond set-up in both games this international break.
The conclusion from the friendlies is that the system contains inherent risks and didn't fill onlookers with confidence. Against an opposition that plays with two strikers, sits back, defends deep and perhaps has a significant aerial threat, it makes sense. It includes an extra center-back to deal with the aerial threat and forces the opposition back due to the extra midfielder. But against Croatia, Mexico looked exposed, and Osorio was forced into a halftime change to a 4-3-3.
A standard 3-4-3, a 3-3-1-3 and the 4-3-3 (with either one or two holding midfielders) will be Mexico's best options heading into the World Cup. Each one makes better use of the wingers, which remains El Tri's strongest group of players.
Tom Marshall covers Liga MX and the Mexican national team for ESPN FC. Twitter: @MexicoWorldCup.