Goals from David Villa and Sergio Ramos secured Spain’s ninth successive win.
Del Bosque said: “It’s been a nice victory, but there were good things and bad in the game.
“We are demanding and we have to play better if possible.
“Maybe the result is better than the game, although we were not bad in possession. But the second half was lacklustre. We needed to be more aggressive in front of goal.”
Del Bosque added: “In South Africa there are very strong opponents and although tonight we’ve overcome France, in the big tournaments there are banana skins that could make you slip up.”