I can see Serena winning the FO again
Should she meet Azarenka or Maria in Paris, she would annihilate both of them
The best chance is for an underdog in the earlier rounds-QF to take her out.
If she gets to the SF, I don't see her losing unless she is injured.
And whether Maria's game is made for clay or not, that is irrelevant when facing Serena as the outcome will be the same.