#2 He also underperformed in the Champions League
The Champions League is the 'holy grail' of European club competition, and a good performance there puts any player in good stead to triumph in individual awards.
Barcelona were knocked out in the quarter-final stage in each of the last three Champions League campaigns, losing to Atletico, Juventus and most shockingly AS Roma in 2016, 2017 and 2018 respectively.
After posting a convincing 4-1 first leg victory over AS Roma in the quarter-final first leg at the Camp Nou last season, very few outside of Roma believed that the tie was still open, as the second leg at the Stadio Olimpico was considered a mere formality.
What followed was one of the biggest shocks in Champions League history, as Roma scored the exact number of goals needed without reply to ensure their qualification, defeating the Blaugrana 3-0.
Lionel Messi failed to score in either leg of the Roma clash, worryingly stretching his scoreless run at that stage to 11 matches. The last time Messi scored a Champions League quarter-final goal was five years ago in April 2013. In that time, Ronaldo has scored 13 goals.
For all of Messi's brilliance domestically where he guided Barca to a double of La Liga (winning the Golden Boot for a record 5th time) and the Copa Del Rey, he largely underperformed on the continent, which is where it really matters.
He posted a paltry (by his standards) goal return of six goals, whereas Ronaldo had another record-breaking season, with his 15-goal haul helping Real Madrid win the UCL for the third consecutive season, while Mo Salah inspired Liverpool to a second place finish with his 10 goals.
In what is clear even to the most fervent of Messi supporter, the Argentine failed to turn up adequately in the Champions League, and was outperformed by others. Therefore, for this succinct reason, he was rightly excluded from the nominees for FIFA Best Player.