Inaki Williams and Diego Llorente hope to use Spain's friendly with Bosnia-Herzegovina to impress coach Vicente Del Bosque ahead of Euro 2016.
The pair are two of 10 uncapped players called up for the pre-tournament friendlies, with layers from Real Madrid and Atletico Madrid absent due to their involvement in the Champions League final.
Neither are expected to force their way into the final 23, but both Williams and Llorente want to use their first experience of the senior national team to make an impact.
"Being here is a prize. I want to learn and enjoy the chance I have been given," said Rayo Vallecano defender Llorente ahead of Sunday's match in Switzerland.
"We're ready for whatever the coach needs, we're here to bring everything to the table if he chooses to count on us.
"He told us we had to enjoy ourselves, that we were learning and this is a great opportunity."
After making his Athletic Bilbao debut in 2014-15, Williams has become a regular first-team fixture this season and has shone with eight La Liga goals.
The 21-year-old's rise has made him one of the top prospects in Spanis football and he was quick to thank those responsible for his development.
Williams added: "I am very proud, I have worked very hard to get here.
"Now it is time to reward all those people who trusted me."
Arsenal defender Hector Bellerin and Madrid youngster Marco Asensio are also part of the squad as Spain continue their preparations to defend the crown they claimed in 2008 and retained in 2012.
After reaching their first World Cup two years ago, Bosnia-Herzegovina were unable to scale the same heights in Euro 2016 qualifying.
They finished third in Group B behind Belgium and Wales, before losing a play-off to the Republic of Ireland 3-1 on aggregate – a 2-0 reverse in Dublin ending their hopes.
Coach Mehmed Bazdarevic has all his big-name players available for the Spain clash, including Roma duo Miralem Pjanic and Edin Dzeko, plus Asmir Begovic of Chelsea.
Sanjin Prcic and Tino Susic will not feature due to injury, but the rest of the squad are raring to go in St Gallen.
"Everyone, especially the younger players, wants to play against a team like Spain," said midfielder Haris Medunjanin.
"I'm glad to be back. We are playing one of the best teams in the world, which is a great challenge."
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