This will be their first meeting.
Ostapenko has much stronger overall results this season. She reached the quarter finals at Wimbledon and of course won the French Open title in May. She has won 72% of matches in 2017 and won 8 of her last 10. On hard courts she has some good results in January with a semi final in Auckland and a third round finish at the Australian Open.
On hard courts they are more even with 57% of matches won. Lepchenko has come through the qualifying rounds this week. She has won 8 of her last 10 on hard courts.
Some value on Lepchenko to take a set. Lay Ostapenko below 1.35 and remove liability if Lepchenko then breaks serve
Update: Lepchenko won 1-6, 7-6, 7-6. She started very poorly and was a set and a break behind before she really got her game going.