Olaf can combine Berserker Rage, Vicious Strikes, and Ragnarok at low life to become deceptively strong.
The bonus healing granted by Vicious Strikes amplifies your Life Steal from all sources as well as heals from allies.
Stay behind minions to make Charm difficult to land, this will reduce Ahri's damage potential significantly.
Ahri's survivability is dramatically reduced when her Ultimate, Spirit Rush, is down.
The stat comparisons shown here feature several critical Olaf against Ahri counter statistics that may help you appreciate the differences and similarities between the pair. For instance, Olaf’s KDA ratio ([kills + assists] / deaths) of NaN is more than Ahri’s ratio of NaN, highlighting that Olaf may be more central to his team's team fighting capacity than Ahri..
Olaf normally has a similar longest kill spree as his enemy does. On average, he receives more damage than Ahri. This is usually reflective of differing health capacities, but it can also show that the one champ has less mobility and thus is not able to kite away from additional damage when poked or engaged.
Both LoL champions are great. Both have their pros and cons. In the game's current meta, Olaf usually fairs equally well when taking on Ahri, with a 50.8% win rate. Thus, Olaf makes an ok counter for Ahri.
While Olaf does have a higher win rate than Ahri, when facing one another, Olaf also has a lower level of difficulty that makes him a less complex character to learn. You still need to be cautious when picking Olaf into Ahri.
Additionally, Olaf has only a small amount of CC and other utility, a similar amount to Ahri. This often makes her just as valuable during team fights, especially when fighting champions with a lot of burst damage.
While there isn't a single best champion in League of Legends, in Olaf vs Ahri matchups, Olaf is the better champ with a similar win rate, less champion complexity, and a similar amount of utility to help out your allied champions during team fights.
Olaf is a decent counter to Ahri. You will do well by focussing your strategy on keeping up your CS and taking out objectives. If you are able to do that, you should be able to stand on your own as Olaf against Ahri.
To truly master Olaf in order to counter Ahri during both the laning and mid / late game phases of League of Legends, you should continue reading to learn a few extra tips and tricks for this matchup. If you listen to the build and stats presented above, you will increase your win rate by a lot and be that much closer to League of Legends pro players.
Olaf often picks up a similar amount of CS compared to Ahri. Champions who on average don't acquire much CS typically don't need much CS to be valuable teammates, such as sup champs. They are capable of scaling well off of their skills, stats, and first items alone. Yet, champs with a lot of CS, such as hyper-carries, usually require a lot of items to be effective. In either case, try to exceed the numbers displayed here to do well.
The most important items to focus on in your Olaf versus Ahri build consist of Sterak's Gage, Experimental Hexplate, and Ravenous Hydra. When Olaf bought at least these three pieces in his build, he did significantly better vs Ahri than with most other commonly used counter builds. In fact, Olaf had an average win rate of 50.8% when playing against Ahri with this build.
To have the greatest chance of defeating Ahri as Olaf, Olaf players should use the Conqueror, Triumph, Legend: Alacrity, Last Stand, Biscuit Delivery, and Approach Velocity runes from the Precision and Inspiration rune sets. Of all the rune sets players used for Olaf vs Ahri counter picks, this mix of runes resulted in the greatest win rate. Notably, these runes gave a 50.8% win rate overall.
By default, tips, stats, and builds on how to beat Ahri as Olaf are displayed for all ranked divisions combined. To scope the stats and builds to an individual division, you should use the selection menu earlier in the counter matchup guide.