The next summer, Lagat won the silver medal, behind El Guerrouj, at the 2001 World Championships in Athletics, and later that summer, at a meeting in Brussels Lagat set the Kenyan National Record and became the second fastest individual ever at 1500m when he ran 3:26.34,
In the 3000m at the 2004 IAAF World Indoor Championships Lagat won his first international gold medal.