Graham Potter believes Daniel James' performances alongside Gareth Bale and against Manchester City prove he is destined for the top.
Swansea City manager Potter admits James' potential transfer value is growing as he is linked with a move to a top six club in the Premier League.
The 21-year-old wing has been in superb form for his club and scored a first Wales goal against Slovakia last month.
"It's just clear at a football level," Potter told BBC Sport Wales.
Potter says James' impressive displays against top Premier League players have underlined his quality.
"It is not for me to announce values and prices," Potter said.
"(But) against Manchester City (in the FA Cup in March) he matches the physicality of Kyle Walker, for example, and runs away from players at that level.
"That's a direct comparison against Premier League players at the very top and you can see his quality.
"He plays alongside Gareth Bale (for Wales) and doesn't look out of place.
"You look at his attributes and how he influences games at Championship level. He causes teams real, real problems.
"It's up to the market to decide the rest, but I'm happy to have him with me and long may it continue."
While Swansea would love to keep James for the long term, a summer transfer is looking likely due to his contract expiring in 2020.
For Swansea, landing a sizeable fee for James could be very significant as they look to balance the books following relegation from the Premier League last season.
When that was suggested to Potter, he said: "We are chatting about ifs and maybes, but I see the general point you're making about a club developing.
"If you have an asset that has outgrown the club and is at a top-six Premier League club (level), you should see that as a positive situation and make your club better.
"We are not in that situation yet because we have a player who is enjoying playing for Swansea City and will continue to do his best for the team."