Ron Vlaar
Ron Vlaar had his spot kick saved by Sergio Romero but the ball appeared to then spin backwards onto the goal-lineGetty

Ron Vlaar was inches away from converting his World Cup semi-final penalty after the ball spun back and stopped on the goal-line, video footage has shown.

Images captured by fans and television cameras at the Arena Corinthians in São Paulo show the ball spinning backwards after Sergio Romero saved the spot kick.

One angle show the ball stop dead on the goal line while the South American goal keeper celebrates the save.

But a different view of the penalty appears to show the Netherlands defender nudge the ball with his shoulder, which would have cancelled out the goal had the ball crossed the line.

Johnny Salazar

Many observers were surprised when the Aston Villa defender was the first Netherlands player to take a penalty against Argentina in Wednesday's shootout, which Argentina won 4-2.

After the contest, Dutch national manager Louis Van Gaal revealed how Vlaar was not supposed to the first player to take their kick but was elevated to the position after two unnamed players shirked the challenge.

"I asked two players to take the first ball before ending up with Vlaar," the incoming Manchester United manager said.

"I felt Vlaar was the best player on the pitch and he has a great deal of confidence. It just goes to show that when push comes to shove, it's not easy to score a goal in penalties."

The 62-year-old also revealed he would have swapped goalkeeper Jasper Cillessen for Newcastle United shot stopper Tim Krul for the penalties - a move he made against Costa Rica in the Netherlands' quarter final clash - but had used up all his available substitutes.

"If I had the opportunity to substitute Jasper, I would've done it, but I had already used three substitutes, so I couldn't do that," Van Gaal explained.