In the world of The Boys, even the other members of Justice League stand-in the Seven can barely hold a candle to Homelander, but Black Noir is the exception. In fact, when it comes to the question of who would win in a fight between the two, the comics have already provided a pretty ironclad answer - and it may surprise you.
Homelander is designed to be a twisted, sadistic version of Superman, with all the Man of Steel’s powers - flight, strength, incredible durability, super senses, and devastating heat vision - but none of his moral fiber. Despite the fact that other characters from The Boys also have DC counterparts, they are still nowhere near Homelander’s power level. So even though Queen Maeve is based on Wonder Woman, who could actually give Superman a run for his money in the world of DC, the fact is Maeve can’t so much as make Homelander flinch, as seen in The Boys #63 when she attacks him and winds up losing her head - literally. However, while Black Noir might seem like a Batman ripoff at first glance, his role in the overall narrative of The Boys is a lot more complex.
In The Boys #65, it’s revealed that Black Noir has actually been a Homelander clone all along. Created as a contingency in case the original Homelander ever went insane, Black Noir has secretly been manipulating the entire story behind the scenes. It was Black Noir - not Homelander - who raped Butcher’s wife, and who heightens the entire conflict between the Seven and the Boys so he will be given the green light to take Homelander’s place. The real Homelander’s record is far from spotless, but he still doesn’t take too kindly to being framed, and a fight ensues. In the end, only one of them is left standing.
Black Noir emerges victorious, with the real Homelander torn to pieces. However, Noir isn’t looking much better; it clearly took everything he had to put Homelander down. Still, it’s little surprise Black Noir came out on top. While Homelander always relied solely on his powers to win battles, Black Noir has all the same abilities plus actual combat training. Noir also seems even more mentally unstable than Homelander, which would likely translate to him being even more brutal in a fight. There’s also the fact that Black Noir was made for the sole purpose of killing Homelander if the need ever arose, so he’s likely been preparing for their showdown all his life. In the end, Homelander never really had a chance.
Still, while Black Noir may have beaten Homelander in as straight of a one-on-one fight as fans could ever have hoped for, he's injured badly enough that Butcher, whose strength and durability is enhanced in the comics, is able to finish the job with the help of a team of marines and some heavy ordnance. Ultimately, Black Noir is the definitive winner in a fight against the Homelander. While the two are matched in power, Black Noir is a feral maniac who has wanted to slaughter Homelander for years, while his originator is a pampered bully who was never expecting to have to meet his match. Happily, with the Boys around, neither villain actually gets to walk away from their final battle.