Gareth Bale said Wales must secure the point they need in a "massive match" with Finland on Wednesday and guarantee promotion to the top tier of the Nations League.
Bale says making the step up to League A is key to facing stronger opposition and gauging the progress the team is making.
Wales are a point clear of second-placed Finland going into the game.
"It's a massive game for us," said Bale at a press conference on Tuesday.
"To win the group and get promoted is something we set out to do at the start.
"It's important for us as a country to get that winning mentality and that feeling going into the Euros in the summer.
"We want to get better and improve and the only way we'll do that is by playing better teams."
Bale is Wales's record goal scorer with 33 but he has not added to the tally in the past 13 months.
However, the 31-year-old says his old sharpness is returning, having had a decent run of fitness and some game time since he re-joined Tottenham Hotspur on loan from Real Madrid.
"The more games I'm playing the better the body is adapting," he said.
"I still need to get a little fitter and sharper but I am getting there.
"It takes a bit of time when you're a bit older, but I am just excited to get back to full fitness and hopefully it won't be too long.
"Leading into the Euros in the summer, that's where I want to be peaking."
Bale was integral to Wales's fairytale run to the Euro 2016 semi-finals, where they lost to eventual champions Portugal.
This time round they may fancy their chances of making the knockout stages again having been drawn in a group with Italy, Switzerland and Turkey.