"There is a entire group of people that deserves an apology," Serena tweets to Tennys Sandgren.
The American's run to the quarters was overshadowed by the content of his Twitter feed.
The Spaniard revealed details of his MRI and plans for rehabilitation on Wednesday.
Next Gen ATP Finals champion is poised for a big year.
Venus sports a rock, but is it an engagement ring?
Suspect second serve cost world No. 3.
Leg injury ends world No. 1's Australian Open hopes.