Osagie, who finished in eighth place at the London 2012 Olympic Games, clocked one minute 46.44 seconds at the Icahn Stadium.
After finishing eighth of nine on his last Diamond League appearance in Doha, it was some improvement for the 25-year-old, though Kenyan Rudisha finished the comfortable winner.
Osagie was helped by a collision involving the chasing athletes, leaving him free to claim second place but a strong start had already put him in a healthy position.
And an impressive final 200m asserted his authority on the race, leaving only Rudisha ahead of him.
Meanwhile, triple jumper Phillips Idowu missed the competition despite indications he was to make his first appearance since London 2012. The Brit is now expected to make his comeback in Rome next month.
- Sports & Recreation
- London 2012 Olympic Games