In other matches of the, seventh seeded Michael Berrer of Germany defeated Frenchman Stephane Robert 7-6, 6-3, while Israeli Dudi Sela, ranked 43, beat American Kevin Kim 7-6 (3), 6-2 to set up a quarterfinal clash against Lacko.
Twenty seven-year-old Ginepri, ranked 100, was today nowhere near to the performance which he produced while ousting top seeded Robin Soderling of Sweden in the first round.
Lacko, ranked 82nd, displayed a steady game on Thursday and was bang on target during big points better. His service was also sharper than his American opponent.
The first set went with serve which led to the tie-break where Lacko seized the initiative to go one set up.
The Slovakian then came back from a 1-3 deficit and broke Ginepri twice to pocket the second set and the match.
Meanwhile in doubles, third seeded Indian duo of Mahesh Bhupathi and Rohan Bopanna progressed to the quarterfinals with a 6-3, 7-6 (5) win over American pair of James Cerretani and Travis Rettenmaier in the rain-affected match. .
After his victory, Lacko told reporters at the post match conference that he produced better game today compared to his first round match.
"For me right now every win in the ATP circuit is important. In the first round, I was rooted to the base line but today I was comfortably placed for aggressive display," he said.