It's a decision that has delighted not only Baxter and the player himself, but also the club's ever-growing supporter base who have really taken to the fly-half since his arrival from Argentine club Deportivo Francesca in October 2010.
Baxter believes there is still "more to come" from Mieres in the future and he is confident that over the next two years at least, the Sandy Park faithful will continue to see the Buenos Aires-born playmaker continue to shine.
The only real issue, however, during the recent talks between both parties was over potential international call-ups, especially the newly-formed Four Nations competition.
"I'm really happy to have signed because I always said I wanted to stay at Exeter," explained Mieres. "I knew it was a difficult contract because of the situation with Argentina, but after lots of talks both parties are happy with the contract.
"Right now it's an extraordinary situation because no one has ever experienced the competition and it's the first year. As I said, I wanted to stay here and Rob wanted to keep me here, so I'm really happy the club - who have been great throughout - have decided to keep me and not oppose any call-up I may get from Argentina."
Having tasted rugby in his native homeland, as well as here in England and also France with both Perpignan and Stade Francais, Mieres says life with the Chiefs is "great" and he feels very settled in Devon.
"This is my second season here and I like it a lot," he says. "I like the way the team play; the way they train, everything really. Right now it's a great place to be and you can see that the club wants big things in the future. At the moment we are fighting hard for that, not just in the Premiership, but also Europe as well."
The Chiefs play their first ever game in the knockout stages of a European tournament when they take on the might of Stade Francais in the Amlin Challenge Cup quarter-finals at Stade Charlety on Thursday, 5 April.