Oh god this is so difficult to pick a winner
All of these wins have been breakthroughs for her, whatever shape & form.
After a lot of consideration, I' am going to go with her win against Vera in the Charleston final
She pretty much played the perfect match. Her forehand & serve were working a treat, her backhand was solid & her focus & composure was just at its best. I mean Vera really couldn't do much to stop Sam's phenomenal play, even she threw a few loopy shots at times & Sam would just hit them with the same ferocity on the forehand & eventually won the point. Plus I mentioned Sam's focus & composure. Even when Vera came back & made it 3-3 all in the 2nd set (could be wrong), it did not deter Sam one bit & she came out & won the last 3 games to seal it. So that in my eyes showed how focused & composed she was, & what impressed me was that she did not panic.
But I mean she showed great focus & composure during those epic matches against Justine, Serena, Elena & even that match at the YEC against Fran where she trailed 4-0, just did not panic at all. So my Top 5 in order:
1. Charleston Final win over Vera
2. US Open 4R win over Elena
3. French Open QF win over Serena
4. French Open 4R win over Justine
5. YEC RR win over Fran (overcame some scar tissue there)