I also agree that Poland will beat Wales but it will be tough especially as Wales are quite stubborn and with Poland having the advantage of most of their players present, it will be difficult for Wales to penetrate them when they meet on the 26th. Poland are just above Wales with three points and I know that eyes will be on both Robert Lewandowski and Gareth Bale to deliver both their teams. I'm also in favor of Poland winning that game by a slim margin.
As usual, everyone is underestimating Wales, and they have their reasons. In the 21st century, Wales has played against Poland six times, and Poland has won all six times. However, we shouldn't underestimate Wales; they are a talented and spirited team. So, the upcoming games will be tough, with both teams at a similar level. Still, Poland has the advantage, and I'll bet on Poland favor.
Wales' erratic performance also makes the situation on the field unpredictable because sometimes they can always play well and make some breakthroughs when they get momentum but in other conditions they play badly especially when the opponent can be below them or equal.
Let's take an example when they managed to win against Croatia in qualifying but after that they did not get good results because they could only win draws in several matches.
The best situation today is that Poland and Wales got a big win and of course this is a good thing before they meet because this will certainly bring some positive impacts, especially in terms of mentality and a strong desire to win.
I think the current situation allows an interesting thing from the match later because although in terms of statistics Poland can always win against Wales but of course Wales also does not want to repeat the defeat again and again especially when their spirit is very good now after a big win against Finland.