Kristina Mladenovic continued her brilliant run in the St Petersburg Ladies Trophy as she booked her place in the final against Yulia Putintseva. France’s world number 51 had already put out Australian Open finalist Venus Williams and then added the scalp of 2016 St Petersburg champion Roberta Vinci in the last eight, before a hard-fought semi-final success over wildcard Natalia Vikhlyantseva.