The manga is still ongoing. Right now they are moving on to the Semifinals of the nationals. So far it appears that the arc is just all the top district schools duking it out. Some of the old familiar teams that Seigaku has gone up against in the past are running into some ridiculously strong people.
spoiler on Eiji...
at this rate.. it seems like Rikkaidai might be playing against Seigaku in the finals.. but then who knows if they will get knocked out by an unknown school. The mystery player still remains to be Yukimura.. and Rikkaidai were last year's National champions... so being previous title holder does say something about him.