Page is using Nations League matches as an opportunity to test his younger and fringe players against elite opposition, and their performances against Poland and the Netherlands have offered encouragement.
With the likes of Gareth Bale, Aaron Ramsey, Joe Allen and Neco Williams rested for Wednesday’s home defeat against the Dutch, it might be that Wales’ team to face Belgium looks a little more like a full-strength line-up.
Striker Kieffer Moore (back), midfielder Joe Morrell (broken toe) and goalkeeper Danny Ward (knee) are out injured.
Belgium will be without Romelu Lukaku after the Chelsea striker was injured during their opening defeat against the Netherlands on 3 June.
“Going into this next one, Wales are going into their fourth game of this camp and we’re going into our third. We’re expecting to see the two strongest squads go head-to-head,” Belgium manager Martinez told BBC Sport Wales.
“We’ll have a bit of an opportunity to share the efforts, to see what the strength is a little bit underneath [the first team] and learn some important lessons for Robert and myself before we make decisions about the final squads for the World Cup.
“You always want to win but the focus in this one is more trying to get strong lessons out of the performances, so we get the right final 26 for the World Cup.”
Wales’ most recent win against Belgium was a 3-1 victory in their Euro 2016 quarter-final.
Belgium have won just two of their seven away games against Wales in all competitions, with those victories coming in March 1997 (2-1) and September 2012 (2-0).
Defeat against the Netherlands on Wednesday ended a 19-match unbeaten run for Wales at home.
Belgium have played more games in Nations League history without any ending in a draw than any other side, winning nine and losing five.
Wales have lost two of their last three games in all competitions, as many as in their previous 14.
Belgium have scored in each of their last 46 games since a 1-0 World Cup semi-final defeat to France in 2018.
Against no side has Belgium’s Kevin De Bruyne scored more international goals than he has against Wales, netting three times in seven appearances.