Ferrero, a former top-ranked player who is currently No. 44, played from the baseline and held serve throughout. He conceded just four points on his serve in the second set.
The 14th-ranked Karlovic hit 17 aces but was broken early in the opening set - the only break of the match.
Ferrero won the first set after the umpire overruled a line call on a forehand from Karlovic and closed out the win on his first match point in the tiebreaker when Karlovic netted a return.
Fifth-seeded Fernando Verdasco of Spain, who used one break in each set to defeat Victor Crivoi of Romania 6-4, 6-4, also advanced.
Feliciano Lopez of Spain won two tiebreakers to beat Agustin Calleri of Argentina 7-6 (2), 7-6 (4), Carlos Moya of Spain fought off a set point in the second set before defeating Michael Berrer of Germany 7-6 (5), 7-6 (6), Guillermo Canas of Argentina beat Andreas Seppi of Italy 7-6 (2), 6-3, and Jan Hernych of the Czech Republic rallied to defeat Roko Karanusic of Croatia 4-6, 6-4, 7-6 (5).
Juventus 95th Best Team In World!
Nadal beats Querrey, Spain leads U.S. 1-0
