Valencia scored an early second half equaliser, after Cody Gakpo put the Dutch into a sixth minute lead, and the result now sees Ecuador within a point of an unexpected second-round place.
The 33-year-old handed the South Americans a perfect start when they beat Qatar 2-0 in Sunday's opening game and his tap-in from close range at the Khalifa International Stadium on Friday ensured a deserved point for his side against the more fancied Dutch.
Ecuador and the Netherlands share top place in Group A on four points - a tally that means the hosts are out of contention.
Qatar had, earlier on Friday, lost a second successive game when they went down 3-1 to Senegal and can no longer finish in the top two places and will play only for pride in their last game against the Dutch on Tuesday.
At the same time, Ecuador will meet Senegal in a decisive encounter, where a point will be enough to see them advance but where a win for the Africans could yet see them usurp Valencia and his team mates and send them home.
That would be a devastating outcome after the feisty showing on Friday where Ecuador outmuscled the Dutch and came within the width of the crossbar from winning.
At the helm was Valencia with his clever passes and probing balls while Moises Caicedo seemed to cover every blade of grass as he put the Dutch off their stride in a striking individual performance.
"They had a few biters, guys who were hot on your heels," said an exasperated Dutch captain Virgil van Dijk afterwards, conceding they made it hard for Louis van Gaal's side to settle into their slick passing.
It did initially look as if it would be an easy evening's work for the Dutch, who, had they won, would have been the first side into the last 16.
Davy Klaassen won possession from Caicedo and let Gakpo take over the play with the young striker thrashing home a left-footed strike for the early lead.
But that was as good as it got for the Dutch, who were slowly swamped out of the match. "In possession they are perhaps not of a world class quality but they sure know how to win the ball," added Van Dijk about the pressing game that saw Ecuador gradually take command.
There were furious complaints at halftime when Pervis Estupinan deflected the ball home but it was ruled out because Jackson Porozo was both offside and standing in front of the goalkeeper and blocking his line of sight.
INDIVIDUAL CONTRIBUTION
Ecuador did not have to wait long, however, for Valencia to turn up trumps again – scoring a sixth successive World Cup finals goal for Ecuador, three in Brazil eight years ago and three now in Qatar.
He was quick to tap in after Dutch goalkeeper Andries Noppert parried Estupinan’s drive, continuing what has been a remarkable individual contribution to his country's cause.
Some 10 minutes later Gonzalo Plato hammered a rocket-like shot against the woodwork that Noppert would have only heard whistle past him but it crashed back into play to the relief of the Dutch.
"We didn’t win because we didn't finish some chances, the opportunities that you get, you need to score," said coach Gustavo Alfaro.
"That's what we lacked. However I am proud to lead this young, talented squad. We are up to the challenge."
