Nacho - a former Spain Under-21 representative - is uncapped at senior level, but his fellow Real Madrid defender Arbeloa said the 23-year-old deserved his chance to appear for the reigning World Cup and European champions ahead of Friday's qualifier in Helsinki.
"I spoke to him yesterday and congratulated him. I'm delighted he's here," Arbeloa said.
"Nacho deserves it because he's worked really hard. I hope he enjoys the experience and hopefully it's not his last with the squad."
Another Real defender Sergio Ramos said their reverse fixture against the Nordic nation - which ended 1-1 in Gijon - was the only warning they needed that the Finns can threaten the star-studded Spanish line-up.
"It's clear that Finland is a team that surprised us because they closed up shop against us from the first minute, and although they didn't create too many chances, (they) managed to score against us," said Ramos, a veteran of 109 international caps.
"That is a lesson we learned about keeping our concentration for the full 90 minutes because they were able to level the score with us on the break which made things difficult for us.
"But I think the positive thing is that we always learn from our mistakes."
Isco - who has the lone cap for Vicente del Bosque's side, coming on a substitute in a friendly with Uruguay in February - said he understood chances were limited when trying to earn a cap for Spain.
"I'm very happy to be in the gaffer's plans again and proud to be part of the national team," the Real midfielder, 21, said.
"I always want to play but I understand that there is a lot of competition and in my position there are a lot of good players.
"I have to try my best and enjoy the experience, I'm delighted to be included.
"Qualifying for the World Cup is very important and we are well aware of what we have to do."
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