Heavy rain in Madrid complicated playing conditions and raised questions over the venue choice, especially with the Santiago Bernabeu available during the men's international break.
"It's not on me to criticise. It's obviously a club decision and I'm sure that UEFA is trying to create the best conditions for the tournament. Of course, the weather is not always in our control," Slegers told reporters.
"But I think we've seen a couple of games lately where the pitch conditions haven't been great and I think that's the next step for women's football to take."
Former Arsenal forward Ian Wright described the playing surface as a "disgrace," on Instagram.
He added that the pitch was worse than Saturday's League Cup final venue, Pride Park, which Chelsea manager Sonia Bompastor criticised as unfit after their victory over Manchester City.