If Maria wins exactly 5 games off Sveta would it be considered a tank?
That is exactly what she needs to qualify to be sure that Sveta won't pass her - 5 games in two sets. So in a sense she hasn't qualified yet and you can't say that she doesn't care how she performs in a match. Of course you could claim that it is still a quasi-tank because she would still doesn't care about that part of the match after she wins 5 games. But I also would like to point you out that in the last match that Maria tanked she won only 3 games of Petrova so she would have to work more harder this time than she would normally like to
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