Although he was not on the scoresheet against Andorra, Johnson picked up the man-of-the-match award for his assists from the right flank.
"I think confidence is really important," Capello said. "When one player like Glen Johnson is in the international team it's important for him. He has improved a lot."
Johnson claims confidence in the England camp is sky high.
"Morale couldn't be any higher," he said. "I think that showed out there today."
The right-back admitted that last year, after England had laboured to victory over Andorra, he did not think they could win their opening seven qualifiers.
"Probably not," he said. "But obviously the lads have done that and they are focused."
He added: "I am over the moon. I am thankful to Capello for choosing me. I know I was on a booking and could have been suspended."