Jo seems to have been playing beautifully up to this point (9 Aces, 0 DF, 68% First serve - winning 71%, 0 BP faced, 3/12 BP created), but, just broken serving for the match.
6-3 5-4*
And the stats are all pretty good, with one exception, 5 break points from 25. Clearly had plenty chances to put the match to bed, including in the final set where she took 1 from 10.
Still, onwards and upwards I guess, lots of aces so at least it looks like technically she started well, just flamed out between the ears.