^
Spoiler Below He was able to overcome his father because he was much, much healthier. He was able to overcome the Haitian because the Haitian was busy suppressing all of Papatrelli's powers at once. He was able to overcome Doyle because his telekinesis is less limited, & he has better mastery of it.
Last night, though, Sylar was completely unconsious, & Matt went at him full-throttle. Also notice that Peter was able to best Sylar's shapeshifting via the element of surprise.
I missed the first half; did they explain what happened to Hiro at all?
And remember, "I'm-a Luigi, number one!"