I can relate with this, i have recently been trying to re-learn Irelia (used to be my main toplaner pre rework) and i got matched against a Singed earlier this evening.
The guy had really good macro and he played the lane well with his W often coming in just in time to screw me over more times than i wana admit........but he apparently lacked experience about what happens when he misses his W or doesnt use it right, so despite a rocky start i came back and beat him pretty badly.
At that point i did not think more about it, i figured he just did not play toplane or against Irelia that much so in the postgame lobby i advised him to be careful about Irelia as Singed when his W misses or is unavailable while she has a easy way to reach 5 passive stacks at which point his teammates suddenly start laughing at me.
I sit there wondering what i had said but then it turns out the guy was Grandmaster, a real topnotch player but he just lacked experience in the matchup enabling me, a tiny fellow who generally plays in low plati elo to eventually beat him, i had mixed feelings about it though since one of his teammates was quite an ass about it.