* Ruiz and Umana miss Costa Rica spot kicks
* Dutch stopper Krul brought on for penalties
* Dutch dominate, hit woodwork three times
* Netherlands play Argentina in semi-final on Wednesday (Adds details, quotes)
By Neil Maidment
SALVADOR, Brazil, July 5 (Reuters) - Netherlands goalkeeper Tim Krul made a dramatic entrance off the bench to save two penalties in a shootout win over Costa Rica on Saturday following a 0-0 draw after extra time, sending the Dutch into a World Cup semi-final with Argentina.
Heavy favourites for the clash, the Dutch dominated but were frustrated by the woodwork and a string of fine stops from Costa Rica goalkeeper Keylor Navas before Netherlands coach Louis van Gaal sent on Krul late in extra time for the shootout.
It was an inspired move as Krul plunged to his left to keep out two Costa Rican kicks while Robin van Persie, Arjen Robben, Wesley Sneijder and Dirk Kuyt held their nerve to score from the spot and give the Dutch a 4-3 shootout win.
The Netherlands, who have reached the final three times but never won the World Cup, will play Argentina in Sao Paulo on Wednesday. Hosts Brazil play Germany in the other semi-final.
"You sit on the edge and think it might go to extra time and penalties and you have to take the team from the quarter-finals to the semis," Krul said. "It's a dream, it's unbelievable."
It was a tough end to a superb campaign for World Cup surprise package Costa Rica, who had already seen off the challenge of three former world champions and were bidding to become the first team from the CONCACAF region to reach the last four since the United States in 1930.
Costa Rica coach Jorge Luis Pinto noted his team left the tournament unbeaten in normal play and praised goalkeeper Navas, who thwarted the Dutch time and time again.
"We have a brilliant, spectacular goalkeeper. What we did on the pitch, what we showed to the world, I think that is crucial. We are not a big power but we demonstrated things, we are leaving very proud," he said.
Returning to the scene of their campaign opening 5-1 mauling of defending champions Spain, the Dutch were a world away from that rampant display in a cagey first 90 minutes of probing play, although they almost broke the deadlock in a late flurry.
After being held by a Costa Rican defence that had conceded just twice in Brazil, Sneijder almost got the breakthrough eight minutes from time only for his free kick to hit the post.
With normal time almost up, Dutch captain Van Persie then found himself in space in the box after some scrambled defending but his driven shot was cleared off the line and onto the bar by Costa Rica midfielder Yeltsin Tejeda.
The Dutch arrived in Salvador as the World Cup's top scorers having rattled in 12 goals in four games, and as extra time began they looked keen to avoid penalties having won just one of their five previous shootouts in major tournaments.
Big centre back Ron Vlaar had a header tipped wide by Navas and Robben, one of the World Cup's standout performers, was a constant threat on the break.
However, in a frenetic finish it was the Dutch who were almost undone on the counter when Jasper Cillessen saved well from Umana before Sneijder thundered a curling effort against Costa Rica's crossbar.
With spotkicks almost upon them, Van Gaal took the unusual step of replacing Cillessen with Krul to help his side against a team who had already tasted glory in an expertly taken penalty shootout with Greece in their last 16 match.
Krul had reportedly been working specifically on saving penalties for seven weeks with Dutch coaches and he looked confident from the moment he arrived on the pitch.
With both sides scoring their first kicks, Costa Rica captain Ruiz saw his low effort tipped wide by the towering stopper, who then produced another save in the same spot to thwart Umana with Costa Rica's fifth spotkick.
"We found among the keepers that Tim Krul was the best to save penalties because he has a longer reach," Van Gaal said.
"We studied their penalties and you can see that Krul picked the right corners. I'm really proud that the work paid off." (Editing by Nigel Hunt)