Mercer, 19, has enjoyed a stellar year for Bath, featuring 12 times in the Premiership and capturing the RPA’s breakthrough player-of-the-year award ahead of more lauded top-flight regulars Ross Moriarty, Joe Marchant, Ellis Genge and Alex Lozowski.
Mercer was overlooked for Argentina in favour of the Curry twins, Tom and Ben, but told The Rugby Paper: “Firstly, I’ve got to congratulate the Currys because it’s a massive achievement for them and it shows that if you put in the hard work you get rewards.
“But I’ve spoken to Eddie, he’s told me what I need to work on and I’d like to show him in a really good way why I think he’s made the wrong decision.
“It’s been a hell of a season for me with Bath and I’ve really enjoyed the way we’ve been playing, which has been reflected in my performances. So I’m really looking forward to going to Georgia with the U20s now and trying to retain our championship.
“It’ll be a big challenge ahead and we’ll be missing a few guys who will be on that senior tour now, but we’ll be going in there with a lot of confidence.”
Mercer began the season on loan at Hartpury College but was rushed back to Bath when injuries struck down Test stars Toby Faletau and Dave Denton.
Since then he has been grateful for the faith shown in him by rugby director Todd Blackadder, explaining: “I’ve worked closely with Todd and with him being a former All Black back rower, that’s really helped my game and boosted my confidence.
“I needed somebody to believe in me and I’ve tried my best to pay him back. I’ve worked hard on my defence and am doing lots more around the park.”
Mercer added: “It’s been brilliant working with guys like Francois Louw and Toby Faletau, too.
“I remember watching Francois when I was a youngster and seeing Toby when he was up-and-coming as well, so to put the same shirts they’ve worn on for Bath this season has been a massive learning curve, but one I’ve really enjoyed.
“Injuries and international call-ups meant I got my chance sooner than expected, but luckily I’ve managed to grab it which is all you can do.”
Bath missed out on the play-offs, but Mercer said: “It’s still been a vast improvement on last season for us. We’ll be in the Champions Cup next season and looking to push into the top four, so everyone will come back into pre-season flying.”
Meanwhile it is understood that Bath centre Max Clark declined the chance to head to the Southern Hemisphere with Wales next month because he has ambitions of playing for England.
Despite being born in Bridgend and having a Welsh mother, the hard-running gainline-buster has lived in England all his life and has worn the Red Rose through all the age-grade ranks.
He was part of the England U20s side that were defeated by New Zealand in the 2015 World Rugby U20s Championship final.