Shenzhen - Eugenie Bouchard's comeback from the concussion she suffered at the US Open was stalled by a 6-4, 6-4 loss to Hungary's Timea Babos at the Shenzhen Open on Thursday.
This week, Bouchard won her first match on tour since slipping and falling in the locker room at the US Open in September and hitting her head.
The sixth-seeded Canadian then reached her first quarterfinal in nearly a year by beating Nicole Gibbs in the second round.
Against Babos, however, Bouchard connected on just 58 percent of her first serves, and failed to convert five break points.
In other matches, top-seeded Agnieszka Radwanska advanced to the semi-finals with a 6-3, 6-2 win over China's Wang Qiang, and Alison Riske of the United States beat Anett Kontaveit of Estonia 6-1, 3-6, 6-3.