Flawless Duet does not have a maximum travel distance, try using it in creative ways.
Defiant Dance is not interrupted by crowd control, try timing it for incoming disables.
Use Bladesurge to cover great distances by targeting low life minions on your way to champion targets.
Save an interrupt ability for when Janna uses her ultimate.
Listen for the charge up sound on Howling Gale in case Janna is trying to hit you with it from off screen or from brush.
Janna's at her strongest when buffing another ally. If you can harass her ally, it will weaken her ability to fight you.
The stats provided here emphasize several valuable Irelia vs. Janna matchup stats that may help you grasp the distinctions between this set of champs. Irelia’s KDA ratio ([kills + assists] / deaths) of NaN is better than Janna’s ratio of NaN, showing that Irelia may be more central to her team's team fighting potential than Janna. This observation is largely a result of the difference in kills.
Irelia normally has a much larger longest kill spree than her foe does. On average, she receives more damage than Janna. 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 escape additional damage when poked or engaged.
Both LoL champs are great. Both have their pros and cons. In the game's current meta, Irelia usually fairs equally well when playing against Janna, with a 49.6% win rate. Thus, Irelia makes an ok counter for Janna.
While Irelia does have a lower win rate than Janna, when they face off with one another, Irelia also has a lower level of difficulty that makes her a less time consuming champion to develop with. You should be careful when picking Irelia into Janna.
Furthermore, Irelia has some amount of CC and other utility, a similar amount to Janna. This makes her just as valuable during teamfights, especially when fighting champions with a lot of burst damage.
While there is not one best champion overall in League of Legends, in Irelia vs Janna matchups, Janna 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 teamfights.
Irelia is a somewhat poor counter for Janna. You will do well by focussing your gameplay on keeping up your CS and destroying objectives. If you are able to do that, you should be able to stand on your own as Irelia against Janna.
If you would like to learn all of the intricacies of Irelia to counter Janna during both the lane and mid / late game phases of League of Legends, you should continue reading to pick up a few extra tricks and insights into this matchup. If you listen to the build and stats presented above, you will grow your win rate significantly and be closer to League of Legends pro players.
Irelia on average picks up much more CS as Janna. Champs who on average don't take many minion kills usualy don't have to have much CS to be effective, such as sup champs. These kinds of champions 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, typically have to have several high cost items to be effective. In either situation, try to do better than the values shown on this page to do well.
The best items to have in your Irelia versus Janna build include Immortal Shieldbow, Blade of The Ruined King, and Death's Dance. When Irelia incorporated at least these three pieces in her build, she performed much better vs. Janna than with many other typical counter builds. In fact, Irelia boasted an average winrate of 49.6% when countering Janna with this build.
To have the greatest chance of crushing Janna as Irelia, you should take the Conqueror, Triumph, Legend: Tenacity, Last Stand, Biscuit Delivery, and Cosmic Insight runes from the Precision and Inspiration rune sets. Out of all the rune combinations players picked for Irelia vs Janna battles, this composite of runes yielded the greatest win rate. Moreover, these runes averaged a 49.6% win rate overall.
By default, tips, statistics, and builds on how to beat Janna as Irelia are displayed for all ranked divisions. To scope the stats and builds to a specific rank, you can use the selection menu earlier on the page.