Brennan Johnson believes Wales deserves the big stage after pushing Belgium all the way to the Nations League.
Wales lost 2-1 to the world number two in Brussels on Thursday to finish bottom of Group A4 with one game remaining.
But Wales will avoid relegation to the Second Division if they beat Poland in their final game in Cardiff on Sunday.
“It was a game of two halves,” said Johnson, whose charming run and cross set the tone for Kiefer Moore’s header as Wales improved in the second half after leading Belgium 2-0 .
“First of all, we lack confidence. We don’t know how good we can be tonight, especially what we can bring.
“We didn’t show any of that. In the second half, we came out with a different mentality and were proud of ourselves.”
The Nottingham Forest striker added on S4C: “Rob Page (Wales manager) told us to believe in ourselves and show why we’re here and I think we did.
“Poland is an important game to stay in this league. It will be a very important game and we will all be ready for it.”
More than 30,000 fans are expected to host Wales at the Cardiff City Stadium on Sunday for the World Cup.
The game against Poland will be Wales’ last game before the World Cup in November, the first time the Dragons have appeared in the final since 1958.
Defender Reece Norrington-Davis said of the Brussels defeat: “We changed form in the second half, we became more compact.
“Winning on Sunday, we did stay up late so all the focus was on that game.
“The current goal is to stay in the top flight of the Nations League.
“In the last Nations League we played some good teams. But it’s a huge improvement and that’s what we want to do next time.”
It was Wales’ first campaign at the top level of the Nations League, having won their group title last time in the second tier.
It didn’t help Wales that Page had to field the main second-tier team in June as he prepared for a historic victory over Ukraine in the World Cup play-offs.
On Sunday, they will again be free of the injured quartet of Aaron Ramsey, Ben Davis, Harry Wilson and Joe Allen. Chris Mepham and Ethan Ampadu were also suspended after taking bookings in Brussels.
But captain Gareth Bale will start after coming off the bench in the 64th minute against Belgium.
After joining training camp from the U.S. on Tuesday night, Bell has only attended one training session, the day before he played for Los Angeles FC.