Actually if you walk towards Fiora and start your combo with Q+E as Pantheon you might bait her W, or just sun her when you're next to her because she'll have a harder time reacting.
Also, just poke and don't let her get your Vitals. Avoid trading unless you know you can win the trade.
Also, Quinn has the same problem vs. Fiora, except that she can't get close to throw her E because her distance's what keeps her safe. Anyway, as Quinn you can poke the hell out of Fiora with your basic attacks and Q, besides, it's hard for her to 1vs1 if you play it smart (wait until she uses her ultimate, then E away, blind her, move to another side while you still attack her and kite her as much as you can, then chase her :p
Should be noted you need to get Ignite for this lane or the guy who'll get dumpstered will be you. Also, a smart Fiora will always win against Pantheon because his Aegis of Zeonia is SO predictable. Mind games and great timing are required to win this.
EDIT: Also, I seriously don't get people who ban Jhin, he is seriously underpowered both in the ADC role and Mid Lane. Just camp the sh*t out of him, he has no escapes.
Also, just poke and don't let her get your Vitals. Avoid trading unless you know you can win the trade.
Also, Quinn has the same problem vs. Fiora, except that she can't get close to throw her E because her distance's what keeps her safe. Anyway, as Quinn you can poke the hell out of Fiora with your basic attacks and Q, besides, it's hard for her to 1vs1 if you play it smart (wait until she uses her ultimate, then E away, blind her, move to another side while you still attack her and kite her as much as you can, then chase her :p
EDIT: Also, I seriously don't get people who ban Jhin, he is seriously underpowered both in the ADC role and Mid Lane. Just camp the sh*t out of him, he has no escapes.