I thought it was blatantly obvious that 18 doesn't scale to 17 anymore.
I'm of the opinion that her most powerful attack couldn't dent him based on the fact he stalemated SSB Goku pretty openly whereas 18 just a year or two prior was barely stalemating SS Goten and SS Trunks.
18 and Krillin have fought evenly but Krillin as of Super has done wayyy more impressive things.
Case in point: Krillin and 18 fight Majora, 18 gets her ass kicked, Krillin proceeds to whoop him. Hell, 18 seems to doubt either of them could take him until Krillin beats him.
Even before Krillin overcame his sense of smell he was fighting on par with him whereas 18 got downed by a single kick. "But Jman, Krillin got downed by Majora multiple times too." That's true, but he wasn't exactly "battle-ready" when it came to those attacks, he was surprised with those attacks, whereas 18 blocked and still got knocked down.
Krillin stands toe-to-toe with God Goku momentarily, and even manages to beat Gohan.
Even if we argue that 18 is marginally stronger (let's get that right out of the way now, if she is stronger it is absolutely not by much), she still might get beaten by his craftiness, as it's super underrated when it comes to his fights.
His Solar Flare x100 will come in handy heavily as well.
Remember this thread is about who would win, not who is stronger. Krillin is very crafty and because of it he's overcome people with way higher power levels then himself.
I mean, Krillin and #18 sparred less than a day before the ToP started, and #18 definitively got the better of him... And that was after Krillin's fights with Goku and Gohan.
If she's even remotely familiar with them(which I'm sure she is, considering she's watched him fight multiple opponents, including Goku and Gohan in DBS), then when she saw him jump into the air and assume this stance: (please log in to view the image)
She'd know to just cover her eyes or somesuch.
Now if(and that's a big IF) he caught her off guard with a Solar Flare and then spammed Destructo Discs, he could have a legit shot at taking her out.
Gohan was still peeking through his arms like an idiot: (please log in to view the image)
The others standing in the immediate vicinity(inc. #18) were unaffected just by turning away or shielding their eyes: (please log in to view the image)