Why is Mbappe leading Golden Boot race despite having same goals as Messi?

France captain Kylian Mbappé is leading the FIFA World Cup 2026 Golden Boot race despite being tied with Argentina captain Lionel Messi on six goals each. Under FIFA rules, assists are used as the first tiebreaker when players are level on goals. Mbappé is ahead because he has registered two assists, while Messi has not recorded any assists so far.