The contest for the interim WBO flyweight title, effectively serving as a final eliminator for the full world title, saw teak-tough Millan outclassed for most of the fight.
Adams commanded the centre of the ring, landing ram-rod jabs to head and body on her way to earning a unanimous verdict with two judges marking her 97-93 and the other 96-94.
She clearly relished the occasion, dancing in and out of range, flashing her trademark smile, displaying an Ali shuffle and occasionally switching to a southpaw stance.
“Every time I switched southpaw she didn’t know what was going on. I can switch hit, and that works to my advantage,” Adams said.
“It was good to get the 10 rounds in. Tough fight. She was there to fight as well. I was chilled, I was cruising. I knew she had a good chin.”
Millan displayed what Adams described as a “tough Mexican style”, but she also allowed the Yorkshirewoman to show some mid-fight tactical adjustments.
“I went out looking for the knockout then halfway in I thought, ‘she’s going to be here for a little bit’, so I changed tactics, and stopped loading up on the heavy shots.
“I could tell from the first bell their game plan was to try and wear me down. They thought I might gas out. I’ve done 10 heavy rounds with the guys in the gym. That was nothing compared to what the lads put me through in camp.”
The next step for Adams, twice an Olympic gold medeallist, looks set to be a tilt at the full world title.
Adams commented: “I want a title shot. December 22 hopefully I’ll be back out, and hopefully we can pin her (reigning world champion Arely Mucino) down. I want that title before the end of the year.”
She added: “I think (on Saturday) everyone got a bit more from me, going the full 10 rounds.
“I’ve boxed all around the world, girls from different countries.
“I’ve been in with the best of them. I don’t think there’s anything new people can show me.”