Messi missed his spotkick in Barca's 1-1 draw at Valencia in the first-leg of their Copa clash.
"Leo is a player that is always above average. He's always ready to play, he's very, very competitive. Sometimes he takes on responsibilities that he shouldn't, but you know my opinion, he always plays well. He always scores goals or gives them," Guardiola said.
"Messi's statistics, taking the shot with so much pressure on him, are spectacular."