I think Sehwag should not have bat as a opener for today's match, He should have sent on second down to control the middle order. He is batteling with his form right now so somebody tell Sehwag, even in world cup he should be the perfect middle order. Don't think about the opener try to bat well in middle first.
When he will be back in his form he can rejoin as the Opener back. Opening should be done by either Robin/Saurav OR Sachin/ Saurav.