Madrid - Spain's 1-0 friendly defeat to France on Thursday showed coach Vicente del Bosque still has to find the right formula to get the best out of forward Diego Costa as he seeks to rejuvenate the team after a woeful World Cup.
Brazil-born Costa's goals for Atletico Madrid last season led to him being called up by his adopted country for the finals and earned him a big-money move to Chelsea, where he has continued his prolific form at club level.
However, after five appearances he has yet to open his Spain account and there is a sense the European champions' playing style, which relies on grinding down opponents with long periods of possession, may not be suited to his more direct approach.
Costa said it was up to him to adapt and was confident of breaking his duck, perhaps as early as Spain's opening Euro 2016 qualifier against Macedonia on Monday.
"I sincerely believe that with work the results will come and that's what I am focusing on," Costa told reporters.
"Things are going very well for me at Chelsea and that encourages me to continue improving."
Del Bosque said the team needed to work harder to create chances for Costa and suggested he is prepared to give the 25-year-old plenty of time to settle.
"Diego Costa has shown what he is capable of, now we have to connect with him, understand him," Del Bosque told Spanish television. "He put in a lot of effort and he is certain to give us positive results."
Although it was with an experimental side, Spain's reverse in Paris showed the 2010 world champions still have some way to go to recapture the form that secured back-to-back European titles with a debut World Cup in between.
Del Bosque, without midfield stalwarts Xavi and Xabi Alonso, who retired after the finals in Brazil, and injured playmaker Andres Iniesta, used the game to try out a number of new faces, including midfielders Raul Garcia and Ander Iturraspe, defender Mikel San Jose and forward Paco Alcacer.
He also gave goalkeeper David De Gea a chance to impress while leaving captain Iker Casillas on the bench.
Spain showed a measure of control against a powerful French team but, worryingly for Del Bosque, they failed to muster a single shot on target and were undone when substitute Loic Remy cracked in a fine effort in the 72nd minute.
"They were missing Xavi, Xabi Alonso, Iniesta, who used to play together with their eyes closed," France coach Didier Deschamps said at a news conference. "Vicente del Bosque is a great coach but he is no magician."
Del Bosque, who will field what is on paper a much stronger side from the start for the Macedonia game, saw "some positives" in the defeat.
"We found it tough to create scoring chances but in general terms it was a good match. We will go forward little by little," he told a news conference.
"We showed we are a good team and the newcomers proved they have what it takes to be with us.
"We are working on regenerating the team but generally we have kept an important core group."
Another positive for Del Bosque was the impact that playmaker Isco had on the match after he replaced Santi Cazorla in the 77th minute.
The 22-year-old has yet to nail down an automatic starting place at his club Real Madrid but linked up well with David Silva and gave Spain an extra edge going forward. (Additional reporting by Julien Pretot in Paris; Writing by Iain Rogers editing by Peter Rutherford)