this is actually a tough battle to call... I do not know if Sinestro can keep Ghost Rider down... and the effects of Ghost Rider's Penance Stare should work well on Sinestro... assuming GR can get to use it
I'm gunna say Sinestro will be able to keep Ghost Rider at bay, and take this fight. However, it would be cool to see Sinestro curl up in the fetal position and cry if Ghost Rider could get close enough to use the Penance Stare.
I think Sinestro has the will to withstand the penance stare. He would probably shake it off and say something like, "Everything I've done I did for the good of Korugar!" Then proceed to beat Johnny Blaze down. My money is on Sinestro.