Rosberg found himself behind his fast-starting team-mate in the early stages but battled past and stayed ahead to the finish.
"My rain set-up finally worked out towards the end there and I made up two places on the re-start," said Rosberg. "Sixth place today is ok and it really is the most that we could have hoped for from this weekend. Michael and I had a couple of battles out there which was fun. We respect each other and you just have to be careful and it all worked out ok. It was a good recovery today but we really need to continue to try and improve our car to have a stronger end to the season."
Schumacher, who has endured a difficult season to date, said he was pleased to have finished where he did considering his starting place of 21st as a result of a ten-place grid demotion.
"I am reasonably happy with today's race, especially for the team," he said. "Coming where Nico and I started, I think we can all be pleased with the result, sixth and seventh places from 14th and 21st on the grid is not too bad, and it is important points for the Constructors' Championship. For some reason, the number seven is somehow connected with me in Spa, so there is a further special feeling here. Without the weather being even crazier, we could not have achieved more today in my view.
"I 'met' Nico twice out on the track today. The first time, I had the better go in a nice racing duel and the second time was right after the re-start where I had to lift a little up into Eau Rouge due to the car in front which Nico used to fly past me. All in all, Spa turned out to be nearly as enjoyable as I had hoped for."