Wales manager Ryan Giggs says his side will learn from their harsh “lesson” of a 4-1 thrashing by Spain.
Wales were without injured forward Gareth Bale as they were completely outplayed on their return to the Principality Stadium.
Next they visit the Republic of Ireland in the Nations League on Tuesday, with Bale likely to be missing again with several other players also doubtful.
“We will be better on Tuesday,” Giggs told BBC Sport Wales.
“You have to give them [Spain] credit, fantastic players, playing at the top level, and they showed that tonight. It was a lesson for us.
“It was a lesson for a lot of the players and one we will learn from and we’ll come back stronger.”
Thursday’s friendly was effectively over as a contest after less than half an hour, as Paco Alcacer scored twice and Sergio Ramos once as Spain seized on feeble Welsh defending.
Wales were playing their first game at the 74,500-capacity Principality Stadium since 2011, and a crowd of 50,232 at least had a late Sam Vokes goal to cheer after Marc Bartra had put Spain 4-0 up.
“Against average teams you have to do the basics right and, against a very good team if you don’t do the basics, you get punished, and that’s what happened,” said Giggs.
“We brush ourselves down, take it on the chin. The last time we were in Cardiff we won 4-1 [against the Republic of Ireland] and were magnificent.
“Tonight we were disappointing. The good thing about football is you’ve always got the next game. That can’t come quickly enough.”
Bale is not Wales’ only injury worry with Tuesday’s Nations League trip to Dublin in mind.
Midfielder Ethan Ampadu was taken off in the second half against Spain, while centre-back Chris Mepham was left out of the squad after injuring himself in training.
“Ethan just extended his knee a little bit. We’ll assess it, see how it is,” added Giggs.
“Chris Mepham got a little knock yesterday in training. Gareth is struggling for Tuesday so we try to take care of the lads and get ready for Tuesday.
“We’ll make a decision in the next couple of days because then we have to prepare for the game. If Gareth is not available we have to prepare to see what team we’re going to play, so we’ll make it sooner rather than later.”
Asked if it looks likely Wales will be without Bale once again in Dublin, Giggs admitted: “Yeah, it does.
“Gareth is probably struggling for Tuesday, the nearer we get to the game. So we are up against it.”
Wales captain Ashley Williams agreed that the performance from Wales was short of what was required.
“It was a tough evening, they are a good team,” he told BBC Sport Wales.
“From our point of view we didn’t do well enough, we didn’t play to the level that we have done in the past.
“All four goals were really sloppy and that’s the thing that hurts a little bit. All four of the goals we could have done better on.
“So that is disappointing, but we’ve got another important game coming up… we switch our focus to Ireland now.”