Murray reached the third round in Madrid last week

Murray, the second seed, broke the big-serving Mirnyi twice in each set to secure a meeting with Czech qualifier Lukas Dlouhy.

"It's difficult against him because he serves well and puts a lot of pressure on by coming to the net," said Murray.

"But today I served well and returned well, and he wasn't able to rush me."

Mirnyi, who has won only one matche since Wimbledon, admitted he had been outplayed.

"Murray surpassed me in all aspects today," said the 30-year-old.

"He neutralized my attacking game with passing shots and there were no doubts about the winner of the match."

606: DEBATE How far can Murray go in Russia?

A good run in Russia would see Murray retain an outside chance of booking a place at the end-of-season Masters Cup.

The 20-year-old is seeded to meet Dmitry Tursunov in the quarter-finals.

The top eight players in the ATP Champions Race earn places at the Masters Cup in Shanghai.

Murray lies 18th, 48 points behind the player in eighth.