Maria Sharapova's first appearance at the Kremlin Cup was short-lived as the five-time grand slam champion was beaten in straight sets by Magdalena Rybarikova, while Angelique Kerber also suffered a first-round exit at the hands of Monica Puig in the Luxembourg Open.
Sharapova arrived home in Russia after securing her first title since returning from a 15-month doping ban at the Tianjin Open - the former world number one beating Aryna Sabalenka in Sunday's final.
Adding a home crown to that list will have to wait, though, as eighth seed Rybarikova completed a 7-6 (7-3) 6-4 victory in Moscow on Tuesday.
Fifth seed Anastasia Pavlyuchenkova also bowed out in her homeland, going down 7-6 (7-2) 6-1 to compatriot Daria Kasatkina.
Pavlyuchenkova won the Hong Kong Open in the early hours of Monday morning following rain delays, so her early exit was no great surprise following such a short turnaround.
Daria Gavrilova was beaten by Pavlyuchenkova in that Hong Kong showdown and the sixth seed put that behind her with a defeat of Kristyna Pliskova, while Julia Goerges, Irina-Camelia Begu, Natalia Vikhlyantseva and Vera Lapko also advanced.
Top seed Kerber's miserable season continued with a 6-3 6-4 loss to Puig on day two in Luxembourg.
The former world number one lost to Puig in the Olympic final last year and the unseeded Puerto Rican repeated the treatment, breaking once in the each set to prevail.
Sixth seed Tatjana Maria also lost to lucky loser Naomi Broady, who sealed an emphatic 6-2 6-2 victory, while struggling former world number five Eugenie Bouchard went down 2-6 6-2 6-3 to Johanna Larsson.
Kiki Bertens, the second seed, made no mistake by seeing off Denisa Allertova 6-4 7-5.