Monaco needed just 75 minutes to beat the Russian 6-2, 6-1 at Club Naval de Campo Las Salinas.
He moved on to face fifth-seeded Spaniard Albert Montanes, who beat Brazilian qualifier Rogerio Dutra Da Silva 7-5, 6-2.
Meanwhile, No. 4 seed Pablo Andujar of Spain was upset by Portugal's Frederico Gil 6-2, 6-1; and France's Jeremy Chardy charged past Argentine Leonardo Mayer 7-5, 6-2. Chardy will face Gil in a quarterfinal on Friday.
On Thursday, Chilean favorite Fernando Gonzalez, a wild card this week, will take on Brazil's Joao Souza. The former Australian Open runner-up Gonzalez has captured this event four times, including as recently as 2009, and was the runner-up in 2005.
The 2012 Vina del Mar champion will collect $71,900.