The British number one, top seed for the tournament in Tokyo, built on his opening straight-sets win over Ivo Karlovic on Tuesday with another convincing performance.
Murray had spoken to Wednesday morning's Independent about the improvement in his general play and mindset since winning his first grand slam at this summer's US Open, his last tournament prior to this week.
He said: "Because winning a slam was so important to me I felt sometimes that I was focusing on the next slam rather than on every tournament and every match.
"Now I feel I can hopefully concentrate better throughout the year and not take my eye off the ball at any tournaments."
That was in evidence as he broke to love in each of Lacko's first two service games to race into a 5-0 lead in less than 20 minutes.
The Slovakian staved off a love set at the last opportunity and made Murray work hard to serve out the set, but the Scot came through 6-1 in 25 minutes.
Another break in the third game of the second set put him further in control and one more was to follow, Murray taking all four of his break points as he wrapped up a 6-1 6-2 win.
Murray will face Stanislas Wawrinka in the quarter-finals after the Swiss number two won a hard-fought three-set battle against France's Jeremy Chardy.
The first two sets went to tie-breaks and the third looked to be heading the same way until Wawrinka recorded only the third break of the match to win 7-6 (7/1) 6-7 (6/8) 7-5.
Third and fourth seeds Janko Tipsarevic and Juan Monaco were in first-round action today and both made progress.
Tipsarevic had to come from a set down, the Serbian beating Gilles Simon 4-6 6-3 6-1 in two hours and 24 minutes.
Monaco had no such problems, cruising past Bulgarian qualifier Grigor Dimitrov 6-2 6-1 in just over an hour.