Main Draw spots for Qualifiers are generally tricky as you'd expect at this level of competition.
You'll get one of:
Vika
Petko
Alizé
Vinci
Kiki
Schmiedlova
JJ
BZS
But, excepting Vika, and I'd give them each a decent shot, if they play well.
With the form she is in JoKo qualifying was never even in doubt, and perhaps Misaki Doi had the best idea by giving up before her match even started.
Heather would also have expected to come through her draw but given her recent form it was by no means a certainty that she would. It's a good thing for Heather that she had to play quailes here as she now has some wins under her belt and can attack R1 with some confidence.
A rematch for Jo, if she comes through it, Vika is the likely R2.
Heather might hope to find a tired JJ, who has today won the Guangzhou title. Winner to play Kerber.
R1: (Q) Johanna KONTA (GBR) 63 vs. Andrea PETKOVIC (GER) [13] 17 (CH 9 10/2011)
H2H: 1-0 2015 US Open R32 Hard 7-6(2) 6-3
R1: (Q) Heather WATSON (GBR) 59 vs. Jelena JANKOVIC (SRB) 25 (CH 1 11/2008)