Canada s Raonic and Slovak Cibulkova both went down in three sets to qualifiers Ricardas Berankis and Vitalia Diatchenko respectively.
Lithuanian Berankis, 24, ousted world number nine Raonic 6-3, 4-6, 6-3 in one hour 52 minutes to level his record with the Canadian big server at 1-1.
Raonic, who enjoyed an opening-round bye, looked slightly rusty from the outset, while Berankis, 116th in the world, broke twice for a one-set lead after 34 minutes.
In the second set, Raonic picked up steam also breaking his rival s serve twice to level at one set all after one hour 16 minutes on court.
But in the deciding set Raonic lost his nerve again allowing Berankis to produce the decisive break to advance into the final eight.
“For me the most difficult thing was coming here not in the shape I wanted to be,” Raonic said. “I was sick for 10 days…and was only able to prepare in the last couple of days.”
“There s not really that much of a heartbreak,” Raonic, who still has a chance to make it into the season-ending ATP World Tour Finals in London, added about his early exit in Moscow.
In the women s event, 2011 champion Cibulkova joined the exodus of seeds falling to Moscow resident Diatchenko, who advanced into the last eight with a 4-6, 6-2, 6-2 victory in their first ever meeting.
The opponents traded breaks throughout the opening set but this year s Australian Open runner-up Cibulkova proved more accurate, earning a 1-0 advantage.
In the second set, Cibulkova, ranked 14th, suddenly produced a catalogue of unforced errors allowing unheralded Diatchenko to break three times to level at one set all.
Diatchenko, who is 140th in the world, broke twice early in the third set for a commanding 4-0 lead and kept it through to face her sixth seeded compatriot Anastasia Pavlyuchenkova, who beat American Alison Riske 6-2, 6-2.
“She played aggressively,” Cibulkova said after the match.
“I held it in the first set and in the second I had my chances but she risked some balls and things started to turn on her side. I made a few mistakes and she stayed aggressive throughout the match and just put me under pressure.”-AFP