Across 1,637 ranked games on patch 16.21 in Master and above, Darius mains win 56.0% of their games in the top lane.
Their most common build appears in 43.0% of those games and wins 55.8% of its 704 games.
It starts 
Doran's Blade and 
Health Potion, completes 
Youmuu's Ghostblade, 
Dead Man's Plate and 
Death's Dance in that order, and takes 
Plated Steelcaps.
Three other builds are played often enough in the top lane to be measured on their own.
In the top lane, Darius mains fare best against 
Aatrox (won 75.6% of 41 games), 
Singed (won 68.2% of 22 games) and 
Ambessa (won 64.5% of 31 games).
Their hardest matchups, the champions that counter Darius, are 
Jax (won 40.0% of 55 games), 
Sion (won 28.6% of 14 games) and 
Olaf (won 42.4% of 33 games).