Monaco spent just 75 minutes against the Russian and now moves on to the quarterfinals, where he will face Spaniard Albert Montanes at Club Naval de Campo Las Salinas in Chile.
Montanes gained the quarters with a 7-5, 6-2 decision over Brazilian qualifier Rogerio Dutra Silva.
Also Wednesday, fourth-seeded Pablo Andujar of Spain fell to Portugal's Frederico Gil 6-2, 6-1. He will take on Jeremy Chardy in Friday's quarterfinal after the Frenchman bested Argentina's Leonardo Mayer 7-5, 6-2.
Four-time Vina del Mar champion Fernando Gonzalez of Chile will play Thursday against Brazil's Joao Souza.