Spanish Olympic coach Luis Milla was relieved after his side put a 2-0 defeat to Senegal at the weekend behind them to record a 1-0 win over Mexico in Cadiz.
Athletic Bilbao's Javi Martinez scored the only goal of the game after 12 minutes with a simple header from a corner, and Milla was especially pleased with the contribution of his experienced players in Martinez, Juan Mata, Adrian Lopez and Jordi Alba.
Milla the told the Spanish Football Federation website: "In Denmark (where Spain won the Under-21 European Championships last summer) Mata, Javi and Adrian were examples for their play and what they brought to the team.
"Jordi has behaved fantastically with the national team. I am happy with his maturity and attitude and I believe they will bring a lot of maturity to the team.
"The sensations left me with the feeling that things are good. We have a problem because only 18 players can be selected.
"We need to have everyone together, we are trying to continue the step we took in Denmark.
"We were strong on and off the field. Mentally it will still be difficult and we know there will be teams that will cause us problems."
Spain open their Olympic campaign on July 26 against Japan at Hampden Park in Glasgow before going on to face Honduras and Morocco.