A few keys ...
-- Playing out of the back. The national team's weak link for years. The USA did better in the second half against Costa Rica -- but that was partly due to the fact that the Ticos were gassed and pulled back.
-- Balance in the lines. Berhalter has stressed having one outside player that likes to cut in and the other who is more of a vertical player. Just like what he did with the Crew. On attack, Lima, the right back, moved into a more central role, giving the midfield an extra player, while Lovitz, the left back, stayed back as the third defender. (Berhalter has stressed, though, the roles of the outside backs could be reversed, depending on who is available and who is the opponent.)
-- One holding midfielder. Michael Bradley and then Wil Trapp provided cover in front of the two central defenders, Aaron Long and Walker Zimmerman, and behind the two attacking midfielders, Cristian Roldan and Mihailovic, but they also were the first line of attack, essentially serving as playmakers.
-- Wing play. Again, no surprise, given the Crew's success during Berhalter's tenure. By spreading the game out, Berhalter believes his team can put itself in dangerous positions. Three of the five goals against Panama and Costa Rica came via assists from wingers -- Baird on the first goal against Panama and Jonathan Lewis on the third goal against Panama and the late winner against Costa Rica.
Trying to fit Berhalter's lineup pieces together remains a puzzle, though where the two most influential pieces are positioned will tell us a lot ...
-- Pulisic? He has mostly played on the right wing in a three-player attack for Borussia Dortmund but played inside for much of the time for the USA in the Hexagonal. Berhalter will likely fit Pulisic into the role Baird played -- out wide on the right -- against Panama and Costa Rica.
-- Adams? He has played as a No. 6 for RB Leipzig, seeing a lot of the ball in two commanding wins, but he doesn't have to be the playmaker for Die Bullen that Bradley or Trapp is for the USA because he has better ball-handlers around him. Adams could be the most impactful in the right back/central midfielder role Lima played.
Paired together on the right side, Pulisic and Adams would give the USA a pair like it has never had before -- and a pair that could be together for a decade.
The left side? Still, a work in progress.
Antonee Robinson (just starting to train again after ankle surgery) gives Berhalter the vertical player he is looking for though his defending leaves, for now, something to be desired. (George Bello is heir apparent at left back though he only just turned 17.) In front of him, Tim Weah is the obvious choice, but he still may end up being a center forward, the position at which he is being used off the bench at Celtic.
Berhalter has not said what he has planned if at all for Darlington Nagbe -- who was rested along with Atlanta United teammate Brad Guzan in January because of their short offseason -- but Nagbe could play the left wing role, tucked in ahead of a more vertical left back, that he occupied for much of Bruce Arena's short tenure or play alongside McKennie in the two attacking midfield spots.
After that, Berhalter has lots of choices, giving us a month, into the first two weeks of the MLS season, to try to fit them together.