Akinfeev denied Koke and Iago Aspas from 12 yards in a shoot-out at Moscow’s Luzhniki Stadium following a 1-1 draw in Moscow on Sunday.
Russia progress to a quarter-final against Croatia in Sochi but Akinfeev did not want to take the credit for his side’s victory.
“Thank God, we were lucky, that’s it,” Akinfeev said.
“In the second half, we were trying to defend.
“We were hoping for penalties and that’s what happened. Thank God.
“I just feel emptied out. Over the whole second half and extra-time we were defending our goal and managed it, we were hoping for penalties because Spain are hard to beat.”