Try to stay away from walls. Ornn is much less strong if he cannot stun you.
Attack Ornn to keep him from creating items in lane.
The stat comparisons shown on this page highlight some valuable Lillia vs. Ornn matchup stats that may help us realize the differences between this pair of champs. As an example, Lillia’s KDA ratio ([kills + assists] / deaths) of NaN is greater than Ornn’s ratio of NaN, indicating that Lillia may be more central to her team's team fighting effectiveness than Ornn. This observation is in large part a result of the difference in kills.
Lillia often has a much larger longest kill spree than her foe does. Commonly, she receives more damage than Ornn. This often reflects different amounts of tankyness, but it can also imply that the one champion has less agility and thus is unable to escape additional harm when poked or engaged.
Both League of Legends champions are great. Both champs have their pros and cons. In League's current meta, Lillia usually wins when facing off against Ornn, with a 55.6% win rate. Therefore, Lillia makes a fantastic counter for Ornn.
While Lillia does have a much higher win rate than Ornn, when facing one another, Lillia also has a much greater learning curve that makes her a more complex champ to pick up and master. You don't need to be too worried when picking Lillia into Ornnas her relative depth means that you may not be able to unleash her full potential without a significant amount of practice beforehand.
Furthermore, Lillia has some amount of utility and CC, a similar amount to Ornn. This makes her just as valuable during teamfights, especially when fighting champions with a lot of burst damage.
While there isn't a single best champion overall in League of Legends, in Lillia vs Ornn matchups, Lillia is the better champion with a noticably higher win rate, more champion depth, and a similar amount of utility to help out your teammates during late stage team fights.
Lillia is a great counter to Ornn. You will do well by focussing your strategy on increasing your CS and taking out objectives. If you can do that, you should hold your own as Lillia against Ornn.
To truly master Lillia in order to counter Ornn during both the laning and mid / late game phases of League of Legends, you should continue reading to learn a few extra lessons on this matchup. If you mind the build and suggestions presented above, you will grow your win rate significantly and be closer to League of Legends pro players.
Lillia usually gets a lot less CS relative to Ornn. Champs who typically don't earn many minion kills typically don't have to have much CS to be effective, such as sup champs. They are capable of scaling properly off of their skills, stats, and first items alone. Yet, champs with a lot of CS, such as hyper-carries, often need many items to be effective. In either situation, try to do better than the values displayed on this page to do well.
The most important items to prioritize in your Lillia versus Ornn build consist of Rabadon's Deathcap, Riftmaker, and Liandry's Torment. When Lillia incorporated at least these three items in her build, she did a lot better versus Ornn than with most other typical counter builds. In fact, Lillia had an average winrate of 55.6% battling Ornn with these items in her kit.
To have the best likelihood of defeating Ornn as Lillia, you should use the Conqueror, Triumph, Legend: Tenacity, Coup de Grace, Magical Footwear, and Cosmic Insight runes from the Precision and Inspiration rune sets. Out of all the runes players chose for Lillia vs Ornn counterpicks, this mix of runes resulted in the greatest win rate. Moreover, these runes averaged a 55.6% winrate overall.
By default, tips, stats, and builds on how to beat Ornn as Lillia are displayed for all ranked divisions. If you want to narrow the stats and builds to a particular player tier, you may use the selection menu located above.