Gai in seventh Gate is a lot faster than Ulquiorra; however, Ulquiorra surely has the durability to stand against Gai's attacks but...
By a week from now, there's no doubt that Gai would utterly destroy Ulquiorra if the hype about the eighth gate turns out to be true.
Round 1: Nagato who wiped out Konoha with shinra tensei, which he was unable to move 6Tailed Naruto with. 7th Gated with Daytime Tiger was able to push back Rikudou Madara who is massively above KN6. I think Ulquiorra would need to release and keep his distance to win.
@taichokage: Kakashi, ironically, is my favorite character lol. But Gai is definitely in my top 10 favorites. Speaking of Kakashi, him and Guy's friendship is one of the best ever. It's not over the top or questionable like Naruto and Sasuke. When they fight you see how much they trust each other and really consider each other to be top flight ninja. THAT is true friendship. Naruto and Sasuke, take notes.