Suggested by iKnowledgeMidnighter is an exceptional hand to hand combatant who can envision how a fight will go down before it even happens. In a pretty intense feat he explains that he can play out a fight in billions of different ways before it starts. It may be some hyperbole on his part, but the fact remains that the Midnighter has defeated opponents like the Martian Manhunter and has enough super strength to even injure Etrigan. Leonardo is strong, but considering Midnighter’s virtual pre-cog abilities in battle he won’t be able to land a square hit. Midnighter wins.
Update 9/28/2019 Leonardo has his Saint Turtle form which is strong enough to turn the tides. This cosmic power can’t be beat. Leonardo wins.