Building on his strong debut showing in Qatar just a fortnight earlier, GasGas Tech3 rider Acosta rose from seventh on the grid to take third in Sunday's grand prix at Portimao, finishing behind the Ducatis of Jorge Martin and Enea Bastianini.
But while scoring a rostrum in only second race weekend was a feat in itself, the 19-year-old also caught the attention with how easily he could pass factory KTM riders, sending his bike up the inside of Miller at Turn 1 on lap five before repeating that move on Brad Binder two tours later.
Having witnessed the contrast between his and Acosta's riding in the intra-KTM battle in Portugal, Miller feels there are a number of things he can learn from the young Spaniard.
"He's not really on top of the bike, he's out of the bike a lot," Miller quipped. "He has everything touching the ground. Looks like his head is about to touch the ground at some point.
"The style is impressive, especially when you look behind. I can only wish to ride like that. I'm a little less stylish, maybe.
"He's riding well, he can put the bike where he wants to. That's a positive thing.
"We have improved this KTM an incredible amount in the last 12 months, he's taking full advantage of it.
"Now we need to use him as a target and try to understand what he is doing differently and learn from him. I'm 29 but I'm still learning every race."
Asked if younger riders are bringing this new riding style to MotoGP, he added: "100%. You only need to look at [Jorge] Martin and him, these guys are touching everything on the ground.
"If you look at my style back in 2016, to what it is now, my style has changed quite a lot.
"But obviously not enough, I need to keep working on it. I'll go back and do some more pilates."
Entering lap five, Binder had got a great run on Miller to the long main straight, which also gave Acosta an opportunity to snatch a position from the Australian into Turn 1.
After Acosta managed to make a pass on Binder as well, neither factory KTM rider could put up a counterattack on the reigning Moto2 champion, who went on to overtake champions Marc Marquez and Francesco Bagnaia before moving to third on the final lap when Maverick Vinales crashed with a gearbox issue.
Miller said he and Binder "had our tongues hanging out" while trying to repass Acosta, but they were simply no match to the satellite KTM rider.
"I didn't really have a chance [against Acosta]," he said.
"Me and Brad got pretty close in the braking zone and I ended up off the kerbs. I left the door open for Pedro.
"Pedro rode fantastic. Once he got past Brad, he kind of just put the hammer down.
"Brad and I both had our tongues hanging out trying to chase him down but we couldn't do anything about it. He looked good on the bike."
