Instead, Romero wasn't just conservative, he was downright stationary – not moving an inch in the opening minute of the fight, and only coming forward intermittently, although his first punch in Round 1 did momentarily stun Adesanya.
In the end, unable to land his usual effective counter strikes on an opponent not willing to constantly engage, while also cautiously hanging back himself given Romero has one-punch knockout power, Adesanya got home on his leg kicks.
He landed 48 significant strikes from 132 attempts, compared to Romero's 40 significant strikes from 89 attempts - easily the lowest output of Adesanya's career.
"Wasn't really what we expected. [Romero] was smart," Gallacher said afterwards.
While Adesanya showed some of his usual bravado in his post-fight Octagon interview, saying he knew Romero would only fight between lulls, he admitted backstage he did not expect such a flat performance.
"You look at a guy like Kelvin Gastelum [UFC 236 opponent], he brought the fight, Robert Whittaker [UFC 243], he brought the fight.
"It takes two to tango, so if I'm trying to fight and you're just standing there going, 'c'mon, c'mon, c'mon' – that's silly.
"I've never been in a boring fight. I don't want to say it's boring, but for me, I was expecting more from him.
"Even in the fifth round, I thought, 'ok, cool, he's coming desperate now'. He's going to bring the fight'.
"I'm just like...waiting for this surge of something. I was the only one willing to dance.
"If you want to come get the belt, come get the belt – don't just stand there and wait for me to come to you. Are you stupid?"
Adesanya will now set his sights on undefeated Brazilian Paulo Costa (13-0), who was to be his original opponent until getting injured.
"I won the fight at the end of the day. I did my best," the expat Whanganui fighter said.
"On my worst night, I still beat the No 3 guy in the world, so that says something to me."
Whanganui fans watch Israel Adesanya's elaborate entrance to UFC 248