With Roger Federer looking good to equal the American Bill Tilden's record of what would be an astonishing sixth straight US Open win, there's renewed speculation on whether the 28-year-old Swiss maestro is the best men's tennis player ever.
Federer's already completely destroyed another record, his 22 straight grand slam semi-finals more than double Ivan Lendl's previous-best run of nine in a row from 1985-88.
The Czech great won three US Open titles and played in eight straight finals in the 1980s and maintains that in his eyes Federer's very close to becoming the greatest player of all time - and has already eclipsed Pete Sampras, who never won all four slams.
Lendl says Federer's the best of the Open era while Rod Laver's the best of the pre-Open period.
But Laver won a calendar grand slam - one set of records Federer's yet to achieve.