Estonia’s Kaia Kanepi fell at the first hurdle in Chicago, losing to Swiss Jill Teichmann 6-7 (3-7), 5-7, after her success in Forth Worth at the weekend.
Kanepi couldn’t handle the battling Teichmann, ranked 38, who broke her first two service games before she had a chance to settle in to the match.
Kanepi fought back, levelling at 5-5, before Teichmann wrapped up the set in a tiebreak.
Level at 5-5 in the second, Teichmann took the next two games to take out the nmtch.
Teichmann faces Magda Linette of Poland in the next round.