"It was hot out there today and I thought we did really well in the first half, scoring from our first three penalty corners which took some pressure off.
"In the second half we let them back into the game. They played really well and we put ourselves under pressure by not holding the ball for long enough periods or finishing chances."
From the opening whistle the Black Sticks played with composure and control, and it wasn't long until they began to take control of the game.
Strikers Gemma Flynn and Sophie Cocks put in plenty of work up front early in the first half and created several great chances.
But it was Forgesson who scored New Zealand's first goal at the World Cup, deflecting in a penalty corner drag flick from Anita Punt in the 18th minute.
Eight minutes later Forgesson was on the scoreboard again after pouncing on a loose ball in the circle and flicking over the goalkeeper who had just blocked a shot.
The Black Sticks rounded out the first half three from three penalty corners with Punt flicking low and hard into the left corner on the stroke of halftime to give her side a 3-0 lead.
Captain Kayla Whitelock added to the score sheet nine minutes into the second half, tapping in a nice bounce pass around the keeper by Sophie Cocks.
The momentum swung as time wore on and after scoring three unanswered goals, Belgium battled desperately in search of an equaliser during the final 10 minutes.
The Black Sticks Women play Korea in their second Pool A game on Tuesday 3rd June at 12:30am (NZ time), with live coverage on SKY Sport 3.
Meanwhile, the Black Sticks Men open their World Cup at 3:30am tomorrow morning (NZ time) against Korea in Pool B.
BLACK STICKS 4: (Krystal Forgesson 2, Anita Punt, Kayla Whitelock)
BELGIUM 3: (Barbara Nelen, Emelie Sinia, Stephanie Vanden Borre)
Halftime: Black Sticks 3-0
