Lionel Messi's humble leadership style is a stark contrast to Cristiano Ronaldo's self-centered attitude, which could spell disaster for Portugal in the World Cup knockout stages, according to former England international John Barnes. Barnes highlights the potential for discord within the Portuguese squad, especially if Ronaldo is benched against top-tier opposition, as his self-belief and demand for the ball could disrupt squad harmony. This situation is further exacerbated by the ongoing success of Messi, who, with his six goals in three matches, has united the Argentina squad and driven them to the top of the group stage. Barnes warns that the pressure on Ronaldo will only increase as Messi continues to shine, potentially leading to a breakdown in team dynamics. The pundit emphasizes the importance of a cohesive team spirit in high-pressure situations, suggesting that Ronaldo's individualistic approach may be his downfall. As Portugal prepares to face Croatia in the Round of 32, the manager's decision regarding Ronaldo's starting role will be pivotal in determining the team's success. Meanwhile, Argentina, led by the humble and respected Messi, appears to be on a path to success, with a united and motivated squad. Barnes concludes by suggesting that the contrast between the two captains' leadership styles could be a defining factor in the tournament's outcome, with Messi's inclusive approach potentially outshining Ronaldo's individualistic tendencies.