Everton's Jack Rodwell shone on his debut as a substitute, while Manchester United striker Danny Welbeck made an impact from the bench.
The England boss also praised Phil Jones and Kyle Walker.
"They are all really good young players and I think they will be really important for the next Euros," he said.
Manchester United's Jones, now a regular in defence at Old Trafford, is only 19, and played in the heart of midfield at Wembley.
Rodwell and Welbeck are 20 and Tottenham full-back Walker, who has established himself in Harry Redknapp's first-choice XI at White Hart Lane this term, is the eldest of the quartet at 21.Continue reading the main story
It was a night when Capello openly accepted England's limitations - and rightly so. He made it clear in his pre-match briefing that no-one could take Spain on at their own game. He knew to do so would be the equivalent of a tactical suicide noteRead more of Phil's blog
"I saw them play without fear, with personality. I can also see that physically and technically they are good enough to play with the seniors," Capello said.
Stand-in captain Frank Lampard's header early in the second half gave England victory against the world and European champions - and left the coach lavishing praise on his emerging group of players.
Capello was also delighted with the "fantastic" displays of central defenders Joleon Lescott and Phil Jagielka in the absence of rested captain John Terry.
"These two centre-backs played a fantastic match," said the Italian. "They were really, really good. Every time Spain tried to pass through them, they were in good positions. They played with big, big confidence."
Tottenham midfield general Scott Parker was another performer identified for praise by Capello, who added: "He gave an incredible performance. He is improving every game. He is an important player.
"He can receive the ball from the back four no problem - a really good player."Continue reading the main story
Joe Hart (age 24)
Glen Johnson (age 27)
Joleon Lescott (age 29)
Phil Jagielka (age 29)
Ashley Cole (age 30)
Theo Walcott (age 22)
Phil Jones (age 19)
Scott Parker (age 31)
James Milner (age 25)
Frank Lampard (age 33)
Darren Bent (age 27)
Stewart Downing (sub) (age 27)
Jack Rodwell (sub) (age 20)
Kyle Walker (sub) (age 21)
Adam Johnson (sub) (age 24)
Gareth Barry (sub) (age 30)
Danny Welbeck (sub) (age 20)
Meanwhile Spain coach Vicente del Bosque, who took off influential midfielder Xavi at half-time, defended his team but admitted they found it difficult to break down England's resolute defence.
"I'm disappointed and angry that we did not win but pleased with the performance we put in," he said.
"There were lots of positives. We had lots of possession. We showed a lot of patience against a side with so many players behind the ball. Maybe we lacked a little speed to get behind them with the ball.
"We've always faced up to problems and found a solution but there was a lack of space and a lack of the final ball. We will be prepared when the big games come next summer.
"We do not approach games in a complacent manner and have not taken these games lightly. We played at full pace. They only had one chance from a free-kick so it proves we dominated the game.
"We just lacked that skilful defining moment. It wasn't happening for us."