Ireland's World Cup hopes were dealt a blow when they lost 6-3 to a talented young Belgian side in Rotterdam.
Wednesday's result means the best finish the Irish can achieve at the World League 3 is fifth place.
Ireland play Spain on Friday to decide which final classification game they will be playing at the weekend.
Timmy Cockram scored Ireland's first-half goal, with John Jackson and Mark Gleghorne netting in the second.
The result means Belgium progress to the semi-finals and are guaranteed a place in next year's World Cup.
"That was Belgium's 19th consecutive win - they are a good side," said Ireland coach Andrew Meredith.
"I thought that after the initial difficult phase in the first 15-20 minutes, we worked hard and got ourselves back into the contest, and probably played some of our better hockey.
"The second half was patchy, and our lapses were punished.
"We are no longer in control of the qualification process, and must regroup as quickly as possible."