That was a massive counterpick matchup that occurred because both teams and every team for that matter were sticking to playing braindead safe ranged top laners.
When a ranged top laner counters a ranged top laner, it gets real bad real fast, especially with jungle pressure. Unlike melee champions who have higher stats and survival tools that typically make diving them a lot harder, ranged champions (yes GP is included here) don't have those tools to potentially fend enemies off in a 1v2. Basically, GP was a fucked pick.
Even still though, this required both mid and bot to not lose, which, in this game, they somehow didn't (pretty damn even between both those lanes w/ no kill trading).
Now if you try to take this knowledge to solo Q, you'll quickly realize it will never work because there will be at the very least cumulative 6 kills between the mid and bot laners before laning ends, putting a swift halt to any hope of top lane relevancy. Kills and trades happen nonstop in solo Q.
Edit: Oh disclaimer here, don't worry about all this nonsense for low elo, top laners can and do hard carry games in lower elo, it's only really high elo where the whole "bot lane meta" starts coming into play. I don't know exactly where the change really occurs but i'd say you'll probably start to feel it during plat-diamond while below you probably won't feel it all but above it's a constant factor.
