They conceded three goals in the opening quarter and another before halftime against a Belgium team who shifted the Black Sticks defence around cleverly and finished in clinical fashion.
The hosts forced more penalty corners but lacked finishing sharpness in striker Stephen Jenness's 200th Test, unlike last week when they stunned the European side 5-4.
Coach Darren Smith admits his side failed to cope with the draining conditions and their slick opponents.
"Belgium are a class side and they took it to us in the first half," he said.
"We let in a few goals we aren't happy with and were a bit wasteful at times so have to take the result on the chin.
"We'll do our best to recover now, there will be some sore bodies tomorrow and it's going to be just as hot again."
For Belgium, Tom Boon scored a double from penalty corner strikes while the other goals went to Victor Wegnez and Loick Luypaert.
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