Having fallen behind to Laura De Neve’s early free-kick and then seen defender Alex Greenwood carried off on a stretcher, the Lionesses turned things around to lead via goals from Lucy Bronze in the 38th minute and Fran Kirby in the 44th.
But Belgium captain Tessa Wullaert equalised in first-half stoppage time before notching the winner with an 85th-minute penalty awarded for a Georgia Stanway handball as England slipped to third in Group A1 with two games to play.
Boss Wiegman, whose side had beaten the Belgians 1-0 in Leicester last Friday, told ITV: “This was a game (where) I think we should have been tighter on the ball.
“We weren’t as great in the tempo. We did create lots of chances, we still dominated the game totally, but at moments we lost the ball and then they were gone on the counter-attack. They had five, six moments like that and then they got two or three chances. So it was really us that made it (for) ourselves so hard.
“They played tough, were very compact, and as soon as they win the ball then they were trying to play the counter-attack, and that’s something we really have to get out of our game.
“And besides that, we did create lots of chances but we just have to do better in the final third.”
She added: “We were sloppy on the ball and they were ready for that. We have to be tight, especially in the build and create, at moments we don’t expect to lose the ball, and we didn’t do that good enough today. That’s a hard lesson for us.”
This competition provides England with the opportunity to secure a Paris 2024 Olympics qualification spot for Great Britain – they need to finish top of the group to have a chance to do that, something they are in danger of failing to achieve after their second defeat in four matches in the pool.
With six points, they are now three behind table-toppers the Netherlands – 1-0 victors over Scotland on Tuesday – and one behind Belgium.
The final two rounds of fixtures see England play the Dutch, who beat them 2-1 in Utrecht in September, at Wembley on December 1 then Scotland at Hampden Park four days later.
Meanwhile, Ives Serneels’ Belgium will host Scotland then face the Netherlands away – two wins for the Red Flames would see England miss out on top spot regardless of how they fare.
Wiegman said: “First of all we have to win with more than one goal against the Netherlands at Wembley, and then we have to win the other game too, because Belgium is in a very good place too.
“We know we have work to do – we always do, but we have put ourselves in a hard position at the moment.”
Greenwood went down around 20 minutes into the contest following an accidental clash of heads with Belgian forward Jassina Blom. She received treatment on the field for about 10 minutes before being placed on a stretcher and taken off.
While it was a worrying scene, a subsequent post from the Lionesses’ official X account said Greenwood was “conscious and talking, and…being monitored by our medical staff.”
And Wiegman said of the Manchester City player: “I haven’t talked to the medical staff yet… She’s alright – when she’s walking, she’s alright.”