The fight was brutal and despite his best efforts, Peter soundly got defeated as he was sent into a wall. He struggled to get up, but couldn't. Black Tarantula was panting, having got his fair bit of bruises himself. He was holding back, but he realized so was Peter. Unlike him though, Peter was doing so subconsciously. Furthermore, Peter was still growing and Carlos figured that Peter would grow even stronger once he was fully an adult.
Had Black Tarantula been a criminal, he knew the fight would've kept going on as Peters objective would've been different.
"I win this round, Spider-Man. And I win because I trained. You fight with heart, but you lack the skill. Your ability to adapt is admirable and this has been the best fight I've had in a long while, but you need to get better, not just for you, but for the people you save," he said before he went off.
When he arrived back to Clary, he was tired yet he looked like he had fun.