Ace striker Gonzalo Higuain found form at the right time striking the winner as Argentina beat Belgium 1-0 at the Nacional Stadium here.
Later in the day, in a bold decision, Dutch coach Louis van Gaal brought on Krul to replace Jasper Cillessen in the final seconds of extra-time after 120 minutes had finished deadlocked at 0-0 at Salvador's Fonte Nova Arena.
Robin van Persie, Arjen Robben, Wesley Sneijder and Dirk Kuyt all made no mistake from the spot to beat Costa Rica goalkeeper Keylor Navas, who had put up a gritty show through the 120 minutes of play.
Earlier, Higuain's powerful angular volley in the eighth minute sealed the match in Albiceleste's favour as they set up a date with the 'Oranje' brigade who had a difficult time in getting past a dogged Costa Rica.
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Krul anticipated correctly as he dived to his left to save the shots from Bryan Ruiz and Michael Umana.
Krul was introduced in the last minute of extra time and hardly got the feel of the ball.
In the first match, having been off-colour during the group stages, Higuain finally showed his class and was quick to react to a pass from Angel De Maria, finishing off with a powerful volley from the top of the box against a fully stretched Thibaur Courtois.
Argentina could have scored one more, in the 13th minute when forward Ezequiel Lavezzi took a crack at goal but was denied by the Belgium defence.