Brennan Johnson believes Wales deserve to be on the big stage after pushing Belgium all the way in the Nations League.
Wales lost 2-1 in Brussels on Thursday against the world’s second-ranked side to stay bottom of Group A4 with one game left to play.
But Wales will avoid relegation to League B if they beat Poland in their final fixture in Cardiff on Sunday.
“In the first, we lacked a lot of belief. We didn’t know how good we could be on this night, and especially what we could bring going forward.
“We didn’t show any of that. In the second half we came out with a different mentality and did ourselves proud.”
The Nottingham Forest forward added on S4C: “Rob Page (Wales manager) told us to believe in ourselves, to show why we’re here, and I think we did that.
“Poland is a massive game to stay in this league. It’ll be a really big game and we’ll all be ready for it.”
Over 30,000 fans are expected to give Wales a World Cup send-off at the Cardiff City Stadium on Sunday.
The Poland game will be Wales’ final match before the World Cup in November, the Dragons’ first appearance at the finals since 1958.
Defender Rhys Norrington-Davies said of the Brussels defeat: “We changed our shape in the second half and we were a lot more compact.
“The immediate target is to stay in the top group of the Nations League.
“In the last Nations League we played some good sides. But this is a massive step up and that’s what we want to be doing next time.”
This is Wales’ first campaign at the highest level of the Nations League, having won their group in the second tier last time out.
They will again be without injured quartet Aaron Ramsey, Ben Davies, Harry Wilson and Joe Allen on Sunday. Chris Mepham and Ethan Ampadu are also suspended after picking up bookings in Brussels.
But skipper Gareth Bale is in line to start after coming on as a 64th-minute substitute against Belgium.
Bale only had one training session after joining the camp late from the United States on Tuesday having played for Los Angeles FC the previous day.