Clearly Bally's service game not very effective today, though pointswise Koryttseva's was no more effective. Bally would never expect to lose to an oppenent who had a 50% serve success rate ( on both 1st and 2nd serves ! ) In fact bizarrely, if you take out her 10 DFs and count serves in play, Koryttseva's 2nd serve was much more effective winning 20 / 30 points ( 66.67% ).
Does look possible injury may have played some part. We will no doubt hear if it did.