There's actually two errors in the puzzle at the moment
The intended solution was posted by Deusovi.
The actual solution is
WHO WILLWIN (i.e. no space)
and then either of the two choices,
This only works if the regex has to match the string at all, but not necessarily match it in its entirety. If the regex is required to implicitly begin with ^ and end with $ so that it must match the entirety of the row or column entry then there is, as posted, no solution possible.
The intended solution would work if the first row instead said
i.e. adding a dot after the +
There are other ways to fix as well, but that way seems straightforward enough.
To meet the condition mentioned in the spoiler above, which I suspect is required, there's a second error which must be fixed for any solution to work. The 7th column is missing a final +, and must be
to satisfy the additional constraint.